Refactor app menu sidebar

* Rename to "app menu" across code
* Move content to dedicated sections/components, introduce app menu links
* Use CSS variable for hover background color across the app

app/components/app-menu/about.gjs

@@ -0,0 +1,63 @@
+import { on } from '@ember/modifier';
+import Icon from '#components/icon';
+
+<template>
+  <div class="sidebar-header">
+    <button type="button" class="back-btn" {{on "click" @onBack}}>
+      <Icon @name="arrow-left" @size={{20}} @color="#333" />
+    </button>
+    <h2>About</h2>
+    <button type="button" class="close-btn" {{on "click" @onClose}}>
+      <Icon @name="x" @size={{20}} @color="#333" />
+    </button>
+  </div>
+
+  <div class="sidebar-content">
+    <section class="settings-section">
+      <p>
+        <strong>Marco</strong>
+        (as in
+        <a
+          href="https://en.wikipedia.org/wiki/Marco_Polo"
+          target="_blank"
+          rel="noopener"
+        >Marco Polo</a>) is an unhosted maps application that respects your
+        privacy and choices.
+      </p>
+      <p>
+        Connect your own
+        <a
+          href="https://remotestorage.io/"
+          target="_blank"
+          rel="noopener"
+        >remote storage</a>
+        to sync place bookmarks across apps and devices.
+      </p>
+      <ul class="link-list">
+        <li>
+          <a
+            href="https://gitea.kosmos.org/raucao/marco"
+            target="_blank"
+            rel="noopener"
+          >
+            Source Code
+          </a>
+          (<a
+            href="https://en.wikipedia.org/wiki/GNU_Affero_General_Public_License"
+            target="_blank"
+            rel="noopener"
+          >AGPL</a>)
+        </li>
+        <li>
+          <a
+            href="https://openstreetmap.org/copyright"
+            target="_blank"
+            rel="noopener"
+          >
+            Map Data © OpenStreetMap
+          </a>
+        </li>
+      </ul>
+    </section>
+  </div>
+</template>

app/components/app-menu/home.gjs

@@ -0,0 +1,32 @@
+import { on } from '@ember/modifier';
+import { fn } from '@ember/helper';
+import Icon from '#components/icon';
+
+<template>
+  <div class="sidebar-header">
+    <h2>
+      <img src="/icons/icon-rounded.svg" alt="" width="32" height="32" />
+      Marco
+    </h2>
+    <button type="button" class="close-btn" {{on "click" @onClose}}>
+      <Icon @name="x" @size={{20}} @color="#333" />
+    </button>
+  </div>
+
+  <div class="sidebar-content">
+    <ul class="app-menu">
+      <li>
+        <button type="button" {{on "click" (fn @onNavigate "settings")}}>
+          <Icon @name="settings" @size={{20}} />
+          <span>Settings</span>
+        </button>
+      </li>
+      <li>
+        <button type="button" {{on "click" (fn @onNavigate "about")}}>
+          <Icon @name="info" @size={{20}} />
+          <span>About</span>
+        </button>
+      </li>
+    </ul>
+  </div>
+</template>

app/components/app-menu/index.gjs

@@ -0,0 +1,38 @@
+import Component from '@glimmer/component';
+import { action } from '@ember/object';
+import { tracked } from '@glimmer/tracking';
+import { fn } from '@ember/helper';
+import eq from 'ember-truth-helpers/helpers/eq';
+
+import AppMenuHome from './home';
+import AppMenuSettings from './settings';
+import AppMenuAbout from './about';
+
+export default class AppMenu extends Component {
+  @tracked currentView = 'menu'; // 'menu', 'settings', 'about'
+
+  @action
+  setView(view) {
+    this.currentView = view;
+  }
+
+  <template>
+    <div class="sidebar settings-pane">
+      {{#if (eq this.currentView "menu")}}
+        <AppMenuHome @onNavigate={{this.setView}} @onClose={{@onClose}} />
+
+      {{else if (eq this.currentView "settings")}}
+        <AppMenuSettings
+          @onBack={{fn this.setView "menu"}}
+          @onClose={{@onClose}}
+        />
+
+      {{else if (eq this.currentView "about")}}
+        <AppMenuAbout
+          @onBack={{fn this.setView "menu"}}
+          @onClose={{@onClose}}
+        />
+      {{/if}}
+    </div>
+  </template>
+}

app/components/app-menu/settings.gjs

@@ -0,0 +1,78 @@
+import Component from '@glimmer/component';
+import { on } from '@ember/modifier';
+import { service } from '@ember/service';
+import { action } from '@ember/object';
+import Icon from '#components/icon';
+import eq from 'ember-truth-helpers/helpers/eq';
+
+export default class AppMenuSettings extends Component {
+  @service settings;
+
+  @action
+  updateApi(event) {
+    this.settings.updateOverpassApi(event.target.value);
+  }
+
+  @action
+  toggleKinetic(event) {
+    this.settings.updateMapKinetic(event.target.value === 'true');
+  }
+
+  <template>
+    <div class="sidebar-header">
+      <button type="button" class="back-btn" {{on "click" @onBack}}>
+        <Icon @name="arrow-left" @size={{20}} @color="#333" />
+      </button>
+      <h2>Settings</h2>
+      <button type="button" class="close-btn" {{on "click" @onClose}}>
+        <Icon @name="x" @size={{20}} @color="#333" />
+      </button>
+    </div>
+
+    <div class="sidebar-content">
+      <section class="settings-section">
+        <div class="form-group">
+          <label for="map-kinetic">Map Inertia (Kinetic Panning)</label>
+          <select
+            id="map-kinetic"
+            class="form-control"
+            {{on "change" this.toggleKinetic}}
+          >
+            <option
+              value="true"
+              selected={{if this.settings.mapKinetic "selected"}}
+            >
+              On
+            </option>
+            <option
+              value="false"
+              selected={{unless this.settings.mapKinetic "selected"}}
+            >
+              Off
+            </option>
+          </select>
+        </div>
+        <div class="form-group">
+          <label for="overpass-api">Overpass API Provider</label>
+          <select
+            id="overpass-api"
+            class="form-control"
+            {{on "change" this.updateApi}}
+          >
+            {{#each this.settings.overpassApis as |api|}}
+              <option
+                value={{api.url}}
+                selected={{if
+                  (eq api.url this.settings.overpassApi)
+                  "selected"
+                }}
+              >
+                {{api.name}}
+              </option>
+            {{/each}}
+          </select>
+        </div>
+      </section>
+    </div>
+  </template>
+}