Add Keybinds List to Help Menu

[EmeraldWither]

This PR adds a keybinds help page to Elastic, since it isn't nicely documented in one place anywhere. The keybinds are added dynamically based on what Hotkeys are registered using HotkeyManager (so adding extra hotkeys should appear here automatically), and are then converted to an intermediatory KeybindCaterory/Keybind class so it can be easily represented, tested, and then rendered to the screen. Everything should be unit tested.

[codecov]

Codecov Report

❌ Patch coverage is 90.06623% with 15 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.47%. Comparing base (3c934b8) to head (bb1364b).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
lib/widgets/keybinds_dialog.dart	91.66%	8 Missing ⚠️
lib/pages/dashboard_page.dart	86.79%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #332      +/-   ##
==========================================
+ Coverage   78.30%   78.47%   +0.17%     
==========================================
  Files          93       94       +1     
  Lines        9439     9565     +126     
==========================================
+ Hits         7391     7506     +115     
- Misses       2048     2059      +11     

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[Gold872]

This looks really good. I'll take a closer look at the KeybindsDialog implementation at a later point (it looks really complex) but I like this addition