Switch DRM HAL policy to _client/_server

This switches DRM HAL policy to the design which enables us to
conditionally remove unnecessary rules from domains which are clients
of DRM HAL.

Domains which are clients of DRM HAL, such as mediadrmserver domain,
are granted rules targeting hal_drm only when the DRM HAL runs in
passthrough mode (i.e., inside the client's process). When the HAL
runs in binderized mode (i.e., in another process/domain, with
clients talking to the HAL over HwBinder IPC), rules targeting hal_drm
are not granted to client domains.

Domains which offer a binderized implementation of DRM HAL, such as
hal_drm_default domain, are always granted rules targeting hal_drm.

Test: Play movie using Google Play Movies
Test: Play movie using Netflix
Bug: 34170079
Change-Id: I3ab0e84818ccd61e54b90f7ade3509b7dbf86fb9