Waltham integration with new compositor

Close for KK M2

Merged in master. Closing time. 

The last two things that are missing from this task:

• receiver needs a bit of changes that I've queued up, specifically,

• , investigation/testing if agl-shell-desktop protocol requires an additional role.

Any other potential follow-up work related/from to this task have been migrated to .

Similar, yes, but after I went a few times over , probably the pipeline is probably a bit more different.

And yes, the remoting plug-in does the same thing, the drm_fb is passed down to get a fd and that fd is passed to the gstreamer pipeline. The remoting plug-in uses the resolution@refresh as modeline. remoting_output_finish_frame_handler and the pipeline seem to set a cap to that refresh value. If none is added, defaults to 60Hz. IDK, at this point what caused.

I've added a WIP version for the compositor I'll be shortly add some sandbox branches for the transmitter and the receiver side.

I've refactored a bit of the receiver in an attempt to split/group some of the functionality. Will ping back here for you to take a look.

Yep,  seems to happen, after a few frames in, and that errno=24 triggered. Remoting plug-in must be doing something to cope with that, as it clearly doesn't exhibit that issue.

Do we use similar pipeline in Remoting plug-in? and do we call drmPrimeHandleToFD like transmitter? I am not sure what is the frequency of calling this in remoting plug-in