DiscordRPC: refactor to use mode enumeration instead of hard-coded options

Also reformat with ruff and commit here because I am an idiot.

…toring

…Windows

XDG_CONFIG_HOME being in the environment would cause legendary to resolve
the config path to the Linux client one while running in Wine

Instead of depending on `.instance()` methods to get the initialized
singletons, pass them as constructor arguments. It should clear up what
is used where and improve both consistency and readability of the code.

and restore them once it is disabled. Wine related settings are stored in
Rare's config and the affected variables are removed from legendary's config

…rom legendary.

This works around a deeper issue with legendary's `check_savegame_state`
generating an exception when it tries to `stat` broken symlinkings. In any
case, this might better in general, as our input is only set when if we are
certain enough it is correct.

…y exists

Add a `validationFinished(bool, str)` signal to indicate that is emitted
when the input validation has finished. The result contains if the input
was valid, and the reason is string form.

The `refresh()` method is meant to be use to refresh re-validate and refresh
the indicator upon request. This can be used when showing the widget to make
sure the existing input is valid.

The validation method checks if the path exists and if the path is writable.

The validation method checks if the path exists and it is writable.

Issue stemmed from the validation slot calling `__on_option_changed`. Instead
locally disable install button and enable verify button when the path changes.
This way once the preparation thread finishes it will enable install button.

…Dialog

…mpat tool

This is here to work around legendary's broken handling for `STEAM_COMPAT_DATA_PATH`
when resolving save paths. The `LegendaryCore.get_save_path` method checks
if `STEAM_COMPAT_DATA_PATH` is set only on a per-game basis and it doesn't
fall back to checking the if the variable is set globally.

…odule is not needed

* SelectiveWidget: move into dialogs, it's the only place it is used
* SelectiveWidget: move with selective dialog

…curate