Add option to close layout launcher when opening a new layout

[aborrero]

Is your feature request related to a problem? Please describe.
I'm frustrated by the layout launcher. I open many layouts over the course of the day, using the keyboard shortcut, but then the layout launcher keeps open after launching the layout. This leads to an accumulation of idle layout launchers opened.

Describe the solution you'd like
A terminator config option to close the layout launcher as soon as it as launched a layout.

[guidomz]

I have this same problem as mentioned in #937