frontend: Escape "&" in non-hardcoded menu items

[Dankirk]

Description

"&" is used to make shortcuts for menu items, so we need to escape non-hardcoded items with "&&".

Applies escaping for these menus:

• profiles menu
• scene collections menu
• projector names
• source types (for plugins)
• transitions menu (for plugins)
• filters menu (for plugins)

Things not touched:

• Hardcoded strings in translation files
• cef/browser menus
• Tools menu items added via api

Motivation and Context

Fixes #12853

How Has This Been Tested?

• Made a profile and scene collection with "&" in their names and tested:
  • activating it
  • export->remove->import->activate
• Tried using projectors, source types, transitions and filters after appending "&foobar" to their menu entries

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[Dankirk]

For future, it's worth taking a look if the escaped menu items should have a default shorcut/accelerator, like the first character of the title. Might help navigating long lists, but could also break some working habits if there is a static item that shares the shortcut character.