csharp: Add gst-rtsp-server bindings
This MR adds API from gst-rtsp-server
to the C# bindings. Three gst_rtsp_stream_transport_*
methods were manually disabled due to compilation errors in the generated code, they don't seem important enough to implement custom fixes there.
I also included the test-launch.c
example from that subproject, ported as RTSPServerExample.cs
. Works fine when compiled with new bindings.