Add Decompiler widget to the default layout

Is your feature request related to a problem? Please describe.

Currently, the Decompiler widget is not shown to the users in the dock in the default layout. Instead, the user need to know that Cutter has a decompiler widget or to look under Windows menu to see it.

Describe the solution you'd like

I'd like to see the decompiler widget as part of the dock in the default layout.

Describe alternatives you've considered

An alternative is to make a check to make sure to show the widget only if at least one decompiler is installed. I don't like this option as I want users to install decompilers and know about this option.