InterpreterWindow: sort language tabs by name
Echo command to the prompt in the output window

The old interpreters echoed the command. And it is nice to see the
confirmation that indeed the system knows you pressed enter, and it is
executing stuff. Otherwise, for many commands, the prompt just clears
and there is no friendly indication that anything else happened.
InterpreterWindow: use context injection

Rather than passing a hardcoded list of services, let's declare them
using @Parameter. That way, when we inevitably need new services in the
future, we do not have to change the API contract in order to pass them
to the constructor, but can instead declare them as new instance fields.

What new services will we need? Well, the PrefService for starters,
since we'll need to persist the interpreter history and active tab
settings.