fixed "string indices must be integers" when attempting to retrieve season images from series providers

fixed "'NoneType' object is not iterable" when retrieving languages from series provider
added retry count of 3 for SiCKRAGE oauth2 token refreshes

Added API login method for SiCKRAGE external API using new SSO API key
Removed SiCKRAGE SSO offline token usage in favour of SiCKRAGE SSO API key
Improved OAuth2 handling for external SiCKRAGE API
Added external series provider API support
Added migration code to convert lang column on tv_shows table to ISO639-3
Added migration code to convert offline token to apikey

Added code to migrate existing config files to new config database
Refactored the term indexer to series provider
Refactored the term indexer_id to series id for tv shows and episode_id for tv episodes
Qualities are now enum classes
Episode statuses are now enum classes
Status / Quality composites are now enum classes
Refactored series provider api to support multiple series providers
Refactored core code to support multiple series providers
Refactored metadata providers config code
Data returned from SR backend to new SR web-ui is json using camelCase naming conventions
Refactored how censored items are generatored and handled for log events
Updated CI script
Fixed seeders / leechers for IPTorrents