Add user confirmation dialog before sending SMS to short code.

Non-system apps now require user confirmation before sending an SMS
to a short code that may potentially cost the user money. The number
is tested against regex patterns for short codes for the country
matching the user's SIM card or network. The user is warned if the
phone number is potentially or definitely a premium SMS number.

The regex patterns are loaded from core/res/res/xml/sms_short_codes.xml.
If the user's country is not found, then phone numbers of 5 digits or less
(excluding known emergency phone numbers) are considered to be potential
SMS short codes.

Command to run test cases:
$ runtest -c com.android.internal.telephony.SmsUsageMonitorShortCodeTest frameworks-telephony

Bug: 5513975
Change-Id: Ic0b483153390e974c632302f3061300bc2a2274a