Add Run utility

Hello,

I have wrote some Code for a rough implementation of the run-utility over at my Fork in the [feature/run](https://github.com/J-Marte/Linux-PowerToys/tree/feature/run) branch. It is a separate Flutter-Application so that it can operate independently. I would like to integrate it into this Project. There are still a lot of things to do before it is stable and release ready (wrap into Gnome Extension, Settings, DBus interface naming, documentation, ...).