Move mms related code from opt/telephony to base/telephony.

In an effort to remove it from telephony-common as that will not be
accessible to other modules, and some of them need mms code like
MmsService, TelephonyProvider, Bluetooth.

Test: basic sanity
Bug: 140763963
Change-Id: I03eda5a5dbd003659a90e2b9f6be9d4c2b767add