Feature/plugin v2 (#284)

* Add "title_title" to slim JSON

* WIP

* WIP

* WIP

* WIP

* Add plugin subscription types

* Revert "Subscription manager"

This reverts commit a612500b0f.

* Use auto overflow tables

cherry-picked from a612500b0f

* Add endpoint for plugin subscription

* WIP

* WIP

* Simplify subscription JSON parsing

* Remove MangaDex files that are no longer needed

* Fix linter

* Refactor date filtering and use native date picker

* Delete unnecessary raise for debugging

* Subscription management API endpoints

* Store manga ID with subscriptions

* Add subscription manager page (WIP)

* Finish subscription manager page

* WIP

* Finish plugin updater

* Base64 encode chapter IDs

* Fix actions on download manager

* Trigger subscription update from manager page

* Fix timestamp precision issue in plugin

* Show target API version

* Update last checked from manager page

* Update last checked even when no chapters found

* Fix null pid

* Clean up

* Document the subscription endpoints

* Fix BigFloat conversion issue

* Confirmation before deleting subscriptions

* Reset table sort options

* Show manga title on subscription manager

src/config.cr

@@ -25,6 +25,7 @@ class Config
   property disable_login = false
   property default_username = ""
   property auth_proxy_header_name = ""
+  property plugin_update_interval_hours : Int32 = 24
 
   @@singlet : Config?