Added cleanup code for orphaned database entries

Refactoring coming episodes class code to resolve performance issues
Refactored names of API v2 class endpoints
Moved startup message to appear after web server is started
Fixed launching browser to use a proper IP address when SR is set to listen on all interface's

Added schedule API v2 endpoint

Fixed issue #SICKRAGE-APP-6PG - '>' not supported between instances of 'datetime.timedelta' and 'int' when running subtitle searcher task

Fixed issue #SICKRAGE-APP-6RK - 'NoneType' object is not iterable when attempting to add and search for a new show
Fixed issue #SICKRAGE-APP-6R4 - 'dict_values' object is not subscriptable

Refactored database setup to only init database once, table creations is now solely handled by alembic upgrades

Fixed issue with database upgrades, refactored database initialization to happen after migrations and upgrades are performed