healthd: start using the new Health hal

Subsequently moves the default board hooks to hardware/interface/health
where the new HAL is defined.

This change removes 'healthd's dependency on libhealthd.<target> static hal.
The dependency has now been *temporarily* moved to the new HAL
implementation in hardware/interfaces/health. 'charger' continues to depend
the static HAL.

Test: Tested healthd with and without a board specific health HAL on
Angler.

Bug: b/32724915

Change-Id: I35b56bacde7ded0517bc960f35538d6ca46e6b06
Signed-off-by: Sandeep Patil <sspatil@google.com>