[sensors] new functions and types for direct report mode

Added functions:

  * registerDirectChannel
  * unregisterDirectChannel
  * configDirectReport

Added structs and enums related to direct report functionality.

Stub default implementation is also included.

Test: compiles and runs
Bug: 30985702
Change-Id: Ia542673e2b180e0aa62c1374cf8c1671bf2f5721