- Reorder to be consistent with other apps
- Remove `<help>` link to Discourse as that tag is intended for
persistent docs rather than a place to ask for help
- Remove deprecated `.desktop` suffix from `<id>`
- Add brand colors
- Update HW requirements to be more in accordance with AppStream
recommendations
This removes a lot of duplicated code, as we can simply reuse the
appdata file. It will also allow us to add release notes without
needing to rewrite them. A simple update in the
`adw_about_dialog_new_from_appdata` method will take care of
displaying the release notes.
This also renames the appdata file from `appdata.xml` to
`metainfo.xml`, as `appdata.xml` is considered a legacy filename.
Jean-François Fortin Tam