Support RGBA input buffers.

This change adds separate EGL shader for RGBA->YUV conversion
and modifies the JPEG compression to render input texture
into temporary framebuffer (doing the compression if necessary).

Bug: 301023410
Test: atest virtual_camera_tests
Test: atest VirtualCameraTest

Change-Id: Id3bd19d4c364691e2b1554fcf78d5f9940754314