Introduce gstreamer-play

This is work in progress...

What is missing:

• Add GstPlay-1.0.gir to gir submodule
• Fix issue with error and warning signals
• Need to check if minimum version of 1.20 is well handled
• Add example similar to https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/blob/main/examples/src/bin/player.rs
• Fix clippy errors in gir generated code