Shortcut to access menu bar items

**Is your feature request related to a problem? Please describe.**
I frequently use Alt + [Some Key] to access the menus below the title bar. Dearpygui unfortunately does not seem to have such a feature, so you must click on the menus by using your mouse, which is very annoying.

**Describe the solution you'd like**
Pressing Alt + [Some Key] should highlight the menu on the top, and the user should be able to press [Enter] to access the menu items.

**Describe any alternatives you came up with**
Another way to solve the problem is to simply abolish the dearpygui's custom menu bar and use the platform default menu bar. On windows that would be ugly though, you cannot make the normal menu bar dark.

**Additional context**
As an example, see an app's menu made without dearpygui (Windows Notepad), after you press Alt: