audio policy: refactor audio record APIs

Refactor audio policy service APIs controlling audio record (startInput, stopInput, releaseInput)
To allow finer grain control per AudioRecord client and prepare for new concurrent capture
policy

Test: AudioRecord CTS test. manual test of capture use cases:
camcorder, OK Google VoIP

Change-Id: I4992fd5a115853c47be5dac5465989eb53f1287c