Modernize `Menu` - Base on `Bar` and address litany of issues

[tig]

Related to:

• Refactor KeyEvent and KeyEventEventArgs to simplify #2926
• Create a new Bar view to replace StatusBar (and eventually MenuBar) #3073
• Fixes #3691 - Adds ViewArrangement.Popover #3852

Todo:

• Menu should use Frame instead of DrawFrame #2539
• Update constructors to add Commands and AddKeyBindings instead of using shortcut and action.
• Update ProcessKey/OnKeyPressed handlers
• Do not allow HotKeys to invoke a menu item if it is not visible. Shotcuts yes, hotkeys no. Terminal.Gui v2.x - Planning & Debate Thread #1940 (reply in thread)
• Shortcut should be Key based, not KeyCode -
• Hotkey should be Key based, not Rune
• Partially Fixes #2975 - Replaces old ContextMenu with new Bar/Shortcut based implementation #4008
• Partially Fixes #2975 - Upgrades UICatalog to Menuv2 #4011
• Update Editor Scenario to use MenuBarv2
• Update Notepad Scenario to use MenuBarv2
• Mark old Menu classes as obsolete - Partial #2975 - Deprecate v1 Menu classes  #4013
  • Rename to LegacyMenu etc...
  • Rename Menuv2 etc... to Menu
• Update MenuBar Scenario (or nuke)
• Update DynamicMenuBar Scenario (or nuke or replace)
• Delete old Menu classes

Others:

• Enable using MenuBar as an alternative for ComboBox #2404
• MenuBar: Support Title so that a Window (with wasteful border) is not needed to show app title #2108

Originally posted by @tig in #2974 (reply in thread)