[WAM] Pull out the protocols straight from the compositor + use wayland-scanner to generate the code

Both protocols are now emebedded into chromium84 source code, these have to be pulled from the compositor. 

agl-compositor installs the protocols into pkgdatadir.

To retrieve it you can use pkg-config like `pkg-config --variable=pkgdatadir agl-compositor-0.0.19-protocols`.

For Cmake I'm using 

pkg_check_modules(AGL_COMPOSITOR_PROTOCOLS REQUIRED agl-compositor-0.0.19-protocols)
pkg_get_variable(AGL_COMPOSITOR_PROTOCOLS_PKGDATADIR agl-compositor-0.0.19-protocols pkgdatadir)

Something similar has to be done when building chromium.

Also, after that is done, need to use wayland-scanner to generate the source code from it. 

Look at alexa-viewer, launcher, homescreen, or cluster-demo-receiver on how that happens with qmake or cmake.