[DropdownMenu][ContextMenu] Implement more solid handling of events when mousing up outside or inside

[benoitgrelard]

There are few issues that have happened over time like #656 which we have patched in quick ways but are really rather due to some deeper issues around how the events should be handled internally.

On top of this, there are a few behaviours that we never implemented because we kept the event handling minimal.

Things like:

• mousing up outside should close the menu (whilst give you enough time on the triggers)
• mousing up on disabled items should close the menu

More here too: #1214

[benoitgrelard]

We've learnt a lot from building Select and can bring those improvements here.