build: Remove charger from recovery unless needed

Most devices do not need charger in recovery -- it does nothing and takes
up precious space.  So remove the charger service from recovery init.rc,
the charger binary, and the charger symlink.

Devices that do actually need the charger in recovery may set:

  BOARD_NEEDS_CHARGER_IN_RECOVERY := true

Change-Id: I23e23c79a3151a62c85a3a405723aa4e892e6d31