separated utils, core, ds and loc-api-v02 from loc-hal into their
own independent packages; simplified loc-pla; moved pla to the
root of project; removed loc-stub.
Change-Id: I373f02f9306646addf55ae90d71c4ba8e3741d09
CRs-Fixed: 2172544
Add DataItemObserver interface in SystemStatus so
that clients can subscribe dataitem events from
SystemStatus. Also moving DateItem and its observer,
subscription classes into HAL
Simplify DataItem class implementation.
Change-Id: I7b2c3fc9dcf67dd6132bbcccda874e3f7ed6fa94
CRs-Fixed: 2041019 2072896