Fix performance of home feed regeneration (#12084)

Fetching statuses from all followed accounts at once takes too long
within Postgres. Fetching them one by one and merging in Ruby
could be a lot less resource-intensive

Because the query for dynamically fetching the home timeline is so
heavy, we can no longer offer it when the home timeline is missing

app/models/status.rb

@@ -282,10 +282,6 @@ class Status < ApplicationRecord
       where(language: nil).or where(language: account.chosen_languages)
     end
 
-    def as_home_timeline(account)
-      where(account: [account] + account.following).where(visibility: [:public, :unlisted, :private])
-    end
-
     def as_public_timeline(account = nil, local_only = false)
       query = timeline_scope(local_only).without_replies