configstore: add configstore@1.0 HAL

This change adds configstore@1.0 HAL which provides static configuration values
to the framework. As a first attempt, a configuration item in the
surfaceflinger (VSYNC_EVENT_PHASE_OFFSET_NS) is choosen and converted to
a HAL function named vsyncEventPhaseoffsetNs().

Design doc: go/design-confighal

Bug: 34314793
Test: build & run. make sure that configstore is up and running.
$ ps -A | grep configstore
Change-Id: Ibc70b14176d2e0144a5745d71ceba49ebc3ca706