Move the compose code to tm-qpr-dev (1/2)

This CL moves all the current Compose code from master to tm-qpr-dev,
which is possible now that all Compose dependencies have been cherry
picked to tm-qpr-dev.

Note that I used the SHA of ag/19398175 for this CL Change-Id and
Merged-In tags, which is the last CL in master that changed code in the
compose/ folder. That way, we make sure that we don't try to merge this
code back into master.

Bug: 231131244
Test: m SystemUIComposeGallery
Change-Id: Ic3efb42d371c6aac8c2a6297a0cb192a780903cd
Merged-In: Ic3efb42d371c6aac8c2a6297a0cb192a780903cd