Add output dataspace to CachedSet rendering

This ensures that:
* The proper color conversion is applied to the rendered output.
* Color information is correctly provided when passing the cached buffer
over to HWC

Also rename dataspace to outputDataspace whenever the dataspace is used
for output, so that it's less confusing than just "dataspace"

Bug: 181192086
Bug: 181192080
Test: libcompositionengine_test
Change-Id: I024ab471a9139209d2a51add145e6b14d9ed3745