Add remote access HAL interface and ref impl.

Add remote access HAL interface and reference implementation. This
CL is a merge of multiple CLs commited in internal master.

Test: Presubmit
Bug: 241170646
Change-Id: I55ba98015055d779a362cac05a9f68650b5b92ab
Merged-In: I332221b303274463dfa5b46d78cf0d81f6045e4b