Telephony cleanup do not merge

This CL removes the PSTN and SIP call service providers.
The connection services will now be looked up by package
manager instead.

This CL also cleanups the telephony connection service code.
Now that the SIP code has been moved out the code can be much
simpler and PstnConnection* and TelephonyConnection* can be
merged.

Change-Id: I2e40c5c64c0d242dc41b680943d7e9209142db5b
(cherry picked from commit 8306b5e6d829c0aa3eacaa12a1cddcf3df7194dc)
16 files changed