Define variables in CarrierConfigManager that mirror those in
SmsManager. These will replace MmsConfig. The literal values had to be
moved into this class because classes in frameworks/base/telephony
cannot reference classes in frameworks/opt/telephony.
There is no change to the SmsManager API, but the data available from
SmsManager#getCarrierConfigValues is moving from mms_config.xml files
into the new carrier config API.
Bug: 21085630
Change-Id: I8a88f46c770ddcb3ac6988c29d86f0ca1f211f4a
9444f4be82