[RTT] Remove the legacy RTT service

Remove the legacy RTT service. RTT requests are already directed to
the new API by a previous CL.

Bug: 65108579
Test: unit tests
Test: WifiRttManagerTest:test_regular_scan_then_rtt_ranging_stress
Change-Id: I436e8bcd2f4e2ba6056870d887eea141fbebae85
5 files changed