libperfmgr: Add a new libperfmgr

This CL is to add a new libperfmgr to manager power hint defined in JSON
config file. The HintManager can be used in powerHAL to load
configuration and do/end hints.

Test: mma, and run unit tests
Bug: 62041945

(cherry picked from commit 9d337a7df3ba6d6a8418f58ed59611678ae7b8cd)

Change-Id: I6f2cb0d6d5c0cb10b0561901215c8e9df4094db0
15 files changed