Port sysprof to GTK 4

This branch provides a port of Sysprof to GTK 4 using libadwaita and pulling in some things that were in Dazzle into Sysprof directly (when necessary).

There is still plenty more we can do. For example, we'll probably want to revamp the recording assistant as the three-grid doesn't work very well and doesn't match where we want to go design wise. But either way, better to land this now for Nightly builds and testing.