Completely rewrite how subscription validation is performed. Optimizes it quite a bit while also adding backend support for the upcoming `dissect` sub-command, where you can resolve any subscription into its 'raw' form for easier debugging when making scripting changes.
Adds the following prebuilt presets:
```
"Single"
"SoundCloud Discography"
"YouTube Releases"
"YouTube Full Albums"
"Bandcamp"
```
which require no config.yaml to use. Usage examples can be found in the `/examples` directory
Adds a new docker image: `ytdl-sub-gui:latest` which is ytdl-sub packaged with VS-Code via LinuxServer.io's code-server image: https://hub.docker.com/r/linuxserver/code-server
Proper documentation will be added later
* [BACKEND] Set python __version__ as date, dynamically update it in make
* set version dynamically
* keep empty
* git ignore __init__
* keep init
* keep
* fix unit test
