Split Interactive console into it's own binary

Plasma had an entire text editor for the script engine in-process.

The method for loading this was very convoluted, it loaded a QML file (in plasma-desktop!) which contained an Item(!) which then loaded a QML component that showed a widget dialog. It also wasn't very discoverable, even when you know this console exists!

It also means loading a very heavy lib KTextEditor in ShellComponents which is very heavy. This will get loaded in things like the logout greeter, which is super slow on the pinephone.

We already had the concept of evaluating a script remotely, we can just hook up the print statement and move the whole executable out.

Technically this is an API break on the plasmashell DBus API, but pragmatically going from void -> something on the return type isn't going to break anything.

(also makes it easier to drop this from p-w in the future)