health: Add default impl of health AIDL HAL

Compared to the HIDL HAL implementation,
- libhealthloop (and the HealthLoop class) is kept
- Create libhealthaidlimpl that replaces libhealth2impl. Fork the implementation because
  libhealth2impl is highly coupled with HIDL’s design rationale. This includes forking:
  - HalHealthLoop
  - Health implementation
- Combine the passthrough Health and hwbinder BinderHealth classes into the AIDL
  implementation of Health. This is because AIDL does not support passthrough transport.
  Separating the implementation for the two transports in HIDL does not make sense for AIDL.
- In HIDL, a BinderHealth is a HalHealthLoop which is composed of a (passthrough)
  Health implementation. As a result of this change, in AIDL, a Health implementation
  is a HalHealthLoop, which associates with the Health implementation itself with a raw
  pointer.
- hidl_death_recipient becomes ScopedAIBinder_DeathRecipient
- Callback becomes LinkedCallback

Test: manual
Bug: 177269435
Change-Id: I76e914117ce09b218cdb9d655f2135d29bb629ae