Add a "Delete..." menu option

I frequently have to delete one or more tables of my database. Currently, I simply select all the tables in the Navigation Sidebar, deselect "Sequel Query", right-click on the tables, and click "Delete..." It would be nice if this option were somewhere in the main nav, ideally with its own keyboard shortcut.

No source file, test, or code entry point is named. Start by tracing the existing “Delete...” action from the Navigation Sidebar and compare it with the main navigation actions; done means selected tables can be deleted from the main navigation and through a keyboard shortcut.

Written by the indexing model from the issue text.