stagefright: add support for named vendor extension parameters for MediaCodec

Relay vendor extension params to the component and populate vendor extension
parameters to the format. Failure to set these parameters is propagated to
the caller. Component may decide whether to fail on invalid/incomplete
settings.

Also add required support:

- propagate more errors from OMX to client, and be specific about
errors we ignore in MediaCodec.configure().
- add AMessage::findAsInt64

Bug: 32746650
Change-Id: I67ee8a5c1d3e65816cdadc28d228721925e2e327