Optimise `if`s - use `match... case` statements instead

[wedebe]

Just noticed this elementary issue... if... if... if... if... if... statements all testing the same variable, not if... else if...

https://github.com/openatv/enigma2/blob/0362939424c4b1a883c0a15c0db83956776ebc81/lib/python/Screens/EpgSelection.py#L965

Suggest using match... case here and anywhere else there are multiple if statements being iterated needlessly.

https://stackoverflow.com/questions/66877130/what-is-the-syntactical-equivalent-to-switch-case-in-python/66877137#66877137

[IanSav]

Probably even faster would be to use a dictionary.

Note that all the EPG code is currently being looked at for a major refactor.

[jbleyel]

Link #3119