Refactor form input styles

* Fix issue where button is rendered taller in flexbox, due to default
  margin on input elements
* Refactor/improve all login and signup views

app/assets/stylesheets/components/forms.css

@@ -1,7 +1,7 @@
 @layer components {
   input[type=text], input[type=email], input[type=password],
   input[type=number], select, textarea {
-    @apply mt-1 rounded-md bg-gray-100 focus:bg-white
+    @apply rounded-md bg-gray-100 focus:bg-white
            border-transparent focus:border-transparent focus:ring-2
            focus:ring-blue-600 focus:ring-opacity-75;
   }