Add a Select2 drop-down to `add-shows` and `edit-show`.
The Select2 enables displaying inline language flag images, this feature deprecated by the native `select` drop-down element on some browsers.
Change run existing TVInfo source language lists through validation (removes ~4 bad items), de-dupe list, get the native names, English names, and three letter abbr.
Change remove marisa-trie requirement from language_data/names.py because nothing in SG calls a function that requires it.
Change update some flags.
Cleanup most init warnings.
Cleanup some vars, pythonic instead of js.
Some typos and python var/func names for Scheduler.
Remove legacy handlers deprecated in 2020.
Remove some legacy tagged stuff.
Cleanup ConfigParser and 23.py
Change cleanup vendored scandir.
Remove redundant pkg_resources.py in favour of the vendor folder.
Remove backports.
Remove trakt checker.
Change remove redundant WindowsSelectorEventLoopPolicy from webserveInit.
Cleanup varnames and providers
Various minor tidy ups to remove ide warnings.
