adb client interface for secure services

This CL exposes a callback-based interface to perform some action for
each resolved pairing/connect service as a function of their hostname,
ip address, and port.

The ADB client can then use this information to either set up secure
connections directly, or to tell the adb host server to do so, or
something.

Bug: 111434128, 119490749

Test: N/A
Exempt-From-Owner-Approval: already approved
Change-Id: I2dd04c322df5b0597859f44703cfd2f3f29fd737