R1:08de131da525

Begin modularizing main menu items

Summary:
Ref T10077. Ref T8918. The way the main menu is built is not very modular and fairly hacky.

It assumes menus are provided by applications, but this isn't exactly true. Notably, the "Quick Create" menu is not per-application.

The current method of building this menu is very inefficient (see T10077). Particularly, we have to build it //twice// because we need to build it once to render the item and then again to render the dropdown options.

Start cleaning this…