stagefright: abstract GraphicBufferSource to interfaces

Create two interfaces from GraphicBufferSource:

a) IGraphicBufferSource for client (ACodec) to configure the graphic
buffer source. IOMX no longer routes these messages and OMX internal
options are removed.

b) IOMXBufferSource for IOMX to send OMX specific callbacks.

Added an |origTimestamp| argument to emptyGraphicBuffer, and restore
the original PTS inside OMX to avoid going back to GraphicBufferSource
to patch the output PTS. In the longer term, we should consider moving
the max PTS gap entirely into OMX (probably as an extension index).

Define newly introduced interfaces using AIDL to facilitate code
development.

bug: 31399200

Change-Id: Ibaf6ca1a0737ba6ba9f83bedc3b06ef358db36cb