Implement custom sort title and sorting titles

[Leeingnyo]

Resolves #182

New

DB

• add column sort_title on ids and titles tables (migration file no.12)

API

• implement /api/admin/sort_title/:title_id
  • name is an optional query parameter and if empty, make sort_title null

Server

• add the name(title) option to sort titles
• use sort_title instead title for sorting titles and entries in auto and title options
• sort titles too
• cache sorted titles
  • make helper methods to remove sorted caches

UI

• add a Sort Title field below the Display Name field in edit modal
• set a placeholder with file title (same with title mentioned in [Feature Request] Custom sort order #182 (comment)) at the Display Name field and the Sort Title field
• restore a display name with the file title when a user submits an empty input

Fixes

UI

• remove callbacks after modal hidden

[Leeingnyo]

It's really complicated to delete columns in sqlite3! haha I didn't know that. Thank you for fixing!

[hkalexling]

Haha no problem. I will test and review the rest of the PR soon.

Happy new year! 🎆

[hkalexling]

Sorry for the long delay. I included the sort_title fields into the API response, and everything else looks good.

Thanks for the PR!