Unified HMI: initial commit

Unified HMI: initial commit

This is the initial commit for RVGPU of Unified HMI.

`Unified HMI` is a common platform that promotes UX innovation
in integrated cockpits and enables flexible information display
from various applications across multiple displays.

`RVGPU` is a client-server based rendering engine
that creates 3D commands on a client device, sends them to a server
for GPU rendering, and displays the results.

- create new layer, meta-uhmi
- create sub-layer, meta-rvgpu
- add 1 feature to enable basesystem, agl-rvgpu

Bug-AGL: SPEC-4744
Change-Id: I9b6f3966e3d5a859787f81c41b584fa686fd1f87
Signed-off-by: Fumiya Kohzu <kohzu.fumiya@jp.panasonic.com>