Refactoring settings

[boldar99]

Most information related to settings has been stored in common.py, and the implementation of settings_dialog.py was not the cleanest.

This PR intends to:

1. make the settings related code type-safe,
2. move the information related to settings to a new settings.py file, and
3. clean up the implementations related to settings.

Most changes are simply moving data to settings.py and extracting methods in settings_dialoge.py (which are sometimes further abstracted to reduce code repetition). Furthermore, some TypedDicts are defined to standardise the data in settings.py.

[RazinShaikh]

This looks like a lot of changes. Can you explain what's going on at the high level?

[jvdwetering]

It looks like Boldi is making my janky implementation less spaghetti-like, by using named dictionary types, and spreading out some of the data from the definition of the Settings class. This is probably a good idea.

[boldar99]

I have updated the description of the PR, intending to explain what's going on.

[RazinShaikh]

Looks good, I have suggested a few changes related to dynamically setting attributes which makes the code difficult to read and maintain

[boldar99]

Okay, I have modified the implementation to use built-in methods instead of tricks with setattr.

[RazinShaikh]

nice, shall we merge it then?