Add "find friends", "invite people", and more to getting started footer (#7803)

- Find friends from Twitter (bridge)
- Invite people (when invites enabled)
- Security (change e-mail/password)
- Developers (create OAuth apps/tokens)

app/javascript/mastodon/initial_state.js

@@ -11,5 +11,6 @@ export const boostModal = getMeta('boost_modal');
 export const deleteModal = getMeta('delete_modal');
 export const me = getMeta('me');
 export const searchEnabled = getMeta('search_enabled');
+export const invitesEnabled = getMeta('invites_enabled');
 
 export default initialState;