Add functionality to hide plugins from quick access menu

[JohnnyCrazy]

Please tick as appropriate:

• I have tested this code on a steam deck or on a PC
• My changes generate no new errors/warnings
• This is a bugfix/hotfix
• This is a new feature

If you're wanting to update a translation or add a new one, please use the weblate page: https://weblate.werwolv.net/projects/decky/

Description

This fixes issue: #317

TODO:

• Add a way to synchronize settings across useSettings calls
• On uninstall of a plugin, also remove it from the settings key.

Screenshots

[JohnnyCrazy]

Alright, this PR should be ready. Some notes:

• I freestyled the UI, so feel free to make suggestions. While the text Hidden from quick access menu is quite long, I didn't just want to put the icon as it feels like it's not descriptive enough on it's own.
• On uninstall, the hidden setting for this plugin is reset. i.e. if you install it again, it will always be visible first.

In the long-term, we should investigate some time to making adding such settings-based features easier. With websockets, we might be able to make a nice two-way sync, for example.

[JohnnyCrazy]

@SteamDeckHomebrew/decky-testers