Add build dependencies for split sepolicy files.

Add build targets for split sepolicy files so they'll appear in the root dir for
on-device compilation.  nonplat_sepolicy will eventually be removed as it should
be provided by a different partition.  Also replace sepolicy.recovery with the
appropriate split components.

Bug: 31363362
Test: Policy builds on-device and boots.
Change-Id: I017dabe6940c3cd20de6c00bb5253274d5a9269b