Fix delete associated files on rename (#3343)

* Fix delete associated files on rename

When the 'move associated files' flag is not enabled, the 'delete non
associated files' flag is enabled, and there are associated files
extensions, the associated files are still deleted when renaming. This
fixes this behaviour.
Fix for https://github.com/SickRage/SickRage/issues/3306

* Rewrite if/else statement for associated files

* Rename all associated files during manual rename

Do not check the list of allowed associated files (configured for post
processing) during a rename.
During a rename, rename all associated files listed in the show dir.
This also fixes the rename of subtitles in a separate subtitle dir.

* Small adjustment

* Update logic for delete non associated files