Add in-app help for CLI options + autodocumentation

[waydabber]

Add some in-app help system to the CLI options. This should possibly auto-generate a help that can then exported to a wiki page as well.

[waydabber]

CLI help will not be localized (it could be, it's just a design choice as CLI commands use English anyway).

[waydabber]

Here is how to invoke help (using HTTP but works with CLI or URL schema integration method as well):

curl ht*tp://localhost:55777/help

The help is dynamically generated and produced in an md format so it's easy to update the integration wiki page with its contents when something changes: https://github.com/waydabber/BetterDisplay/wiki/Integration-features,-CLI

Help can be specific, so the following example will only print help for the set and get operations, feature parameter and brightness feature (as an example):

curl ht*tp://localhost:55777/help/get/set\?feature=brightness