Migrate Config.java to use the new *.isEnabled() functions

This change moves determination of whether we should start a profile or
not over to the individual profile level isEnabled() functions. These
functions all use the sysprops internally to return if the profiles
themselves think they should be started/enabled/supported or not.

Tag: #refactor
Bug: 217448211
Test: atest BluetoothInstrumentationTests
Merged-In: Id725b36c2a8975b3c1d0fc60a4e22b302d29bfc4
Change-Id: Id725b36c2a8975b3c1d0fc60a4e22b302d29bfc4