Various code cleanup (#1782)

* Remove duplicate in_chosen_languages definition

* Use `DEFAULT_FIELDS_SIZE` instead of `MAX_FIELDS` to reduce code differences with upstream

* Remove duplicate annotation

* Fix incorrect cross-flavor imports

* Remove deprecated `hide_network` setting (replaced by account column)

* Remove unused KeywordMutesHelper

* Remove trailing spaces

* Remove commit_hash from InstancePresenter, as it has been unused since mid-2017

app/javascript/flavours/glitch/features/report/thanks.js

@@ -8,7 +8,7 @@ import {
   unfollowAccount,
   muteAccount,
   blockAccount,
-} from 'mastodon/actions/accounts';
+} from 'flavours/glitch/actions/accounts';
 
 const mapStateToProps = () => ({});