Migrate Modern theme to separate Flavour

app/javascript/flavours/modern-glitch/theme.yml

@@ -0,0 +1,49 @@
+#  (REQUIRED) The location of the pack files.
+pack:
+  admin:
+    - packs/admin.jsx
+    - packs/public.jsx
+  auth: packs/public.jsx
+  common:
+    filename: packs/common-modern.js
+    stylesheet: true
+  embed: packs/public.jsx
+  error: packs/error.js
+  home:
+    filename: packs/home.js
+    preload:
+      - flavours/glitch/async/compose
+      - flavours/glitch/async/getting_started
+      - flavours/glitch/async/home_timeline
+      - flavours/glitch/async/notifications
+  mailer:
+  modal:
+  public: packs/public.jsx
+  settings: packs/settings.js
+  sign_up: packs/sign_up.js
+  share: packs/share.jsx
+
+#  (OPTIONAL) The directory which contains localization files for
+#  the flavour, relative to this directory. The contents of this
+#  directory must be `.json` files whose names correspond to
+#  language tags and whose default exports are a messages object.
+locales: locales
+
+#  (OPTIONAL) Which flavour to inherit locales from
+inherit_locales: vanilla
+
+#  (OPTIONAL) A file to use as the preview screenshot for the flavour,
+#  or an array thereof. These are the full path from `app/javascript/`.
+screenshot: flavours/glitch/images/modern-preview.jpg
+
+#  (OPTIONAL) The directory which contains the pack files.
+#  Defaults to the theme directory (`app/javascript/themes/[theme]`),
+#  which should be sufficient for like 99% of use-cases lol.
+
+pack_directory: app/javascript/flavours/glitch
+
+#  (OPTIONAL) By default the theme will fallback to the default theme
+#  if a particular pack is not provided. You can specify different
+#  fallbacks here, or disable fallback behaviours altogether by
+#  specifying a `null` value.
+fallback: