Add Mastodon API service class, auth token config

Add a new REST API service class to keep things DRY

app/services/mastodon_manager_service.rb

@@ -0,0 +1,22 @@
+#
+# API Docs: https://docs.joinmastodon.org/methods/
+#
+class MastodonManagerService < RestApiService
+  private
+
+    def base_url
+      @base_url ||= "#{Setting.mastodon_public_url}/api"
+    end
+
+    def auth_token
+      @auth_token ||= Setting.mastodon_auth_token
+    end
+
+    def headers
+      {
+        "Content-Type" => "application/json",
+        "Accept" => "application/json",
+        "Authorization" => "Bearer #{auth_token}"
+      }
+    end
+end