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/models/status.rb

@@ -322,10 +322,6 @@ class Status < ApplicationRecord
       visibilities.keys - %w(direct limited)
     end
 
-    def in_chosen_languages(account)
-      where(language: nil).or where(language: account.chosen_languages)
-    end
-
     def as_direct_timeline(account, limit = 20, max_id = nil, since_id = nil, cache_ids = false)
       # direct timeline is mix of direct message from_me and to_me.
       # 2 queries are executed with pagination.