[Feature] Revamped group and loadout selection dialogs

[empollak]

Pull Request Description

When merged this pull request will:

• Update the group and loadout selection dialogs to match the respawn dialog
• Move UI elements into ui_defaults.hpp for reuse

The loadout locker UI can be pulled up with scroll wheel action or ACE interact:

Group picker UI when squad markers are disabled:

Group picker UI when squad markers are enabled (map pans to selected squad, if it is visible):

I don't know if my organization is the best on this one. ui_defaults.hpp is a bit full now and ui_macros.hpp might imply it's more general than it should be. Open to feedback.

Release Notes

The group selection UI and loadout locker UI have been updated.

IMPORTANT

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[empollak]

contributes to #284 but doesn't get all of them