Add the ability to trigger context menu entries using key bindings

[gdaniel]

• I have checked that this feature has not yet been suggested by someone else.

Similarly to #1626, it should be possible for a specifier to define a KeyBinding (key along with ctrl, alt, meta) for a context menu entry.
As for diagrams, we want to:

• Display the key binding in the contextual menu
• Support multiple key bindings for an entry

Executing an entry via its key binding should be able to trigger impact analysis.