Duplicate managment functionality

[NarwhalHorns]

Adds a 'Duplicate Management' page that searches for and displays any potential duplicates found in the user's library for management.

Possible Duplicates Tab - display potential dupes to remove/hide

• Currently gets all library manga and searches for duplicates on each one using a simple fuzzy search of the title {% title %}
• Displays any duplicates found against each manga
• Each entry can be unfavorited or 'hidden' as a duplicate
  • Key manga (manga checked against) can be hidden to hide all duplicates found against it at once.

Hidden Duplicates Tab - manage duplicates marked as hidden in case they need changing

• Lists all hidden duplicates against each entry
• Each can be 'unhidden' to put them back in normal duplicate search
  • KeyManga can be unhidden to unhide whole row of dupes against it

General

• Shows chapter count on entries
• Can backup and restore hidden duplicates

Possible Duplicates Tab	Hidden Duplicates Tab

Change automatic duplicate search match level for when adding new manga	Change duplicate search match level on possible duplicates screen

Confirm removing manga and chose to delete downloads

Empty Possibles screen	Empty hidden dupes screen

Problems

• Fuzzy search just finds too much shit. (e.g. entries with single common word like 'ring' find ANYTHING containing substring 'ring' which is just insane.)
  • Maybe multiple levels of search depth? i.e. exact match, word fuzzy, full substring fuzzy.
  • Probably needs more complex search algorithm todo later if desired
  • Perhaps configurable percentage match threshold todo later if desired

TODO:

• Animate removing items or something? bit sudden atm not changing list manually now
• Remove favorite popup check
  • check delete downloads on remove
• Reload tabs on change (not sure how to do this, scrapped together the tab functionality so might need re-working for that)
• Backup and restore hidden duplicates
• Probably wanna make them smaller/change the list design a bit, feels too packed atm?
  • Make duplicate list item size configurable (by width?)
• Some logic to not show duplicate (hah) duplicate lists i.e. when id1 = id2. it is listed one for each one
• Sort duplicate list order
  • alphabetically
  • duplicate count