Implement some support for server-side status translation. Do this by:
- Implement support for the `api/v1/instance` endpoint to determine if
the remote server supports translation.
- Create new `ServerCapabilities` to allow the app to query the remote
capabilities in a server-agnostic way. Use this to query if the
remote server supports the Mastodon implementation of server-side
translation
- If translation is supported then show a translate/undo translate
option on the status "..." menu.
- Fetch translated content from the server if requested, and store it
locally as a new Room entity.
- Update displaying a status to check if the translated version
should be displayed; if it should then new code is used to show
translated content, content warning, poll options, and media
descriptions.
- Add a `TextView` to show an "in progress" message while translation
is happening, and to show the translation provider (generally
required by agreements with them).
Partially fixes#62
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Co-authored-by: sanao <naosak1006@gmail.com>