Bug 22594: Validate SMS messaging numbers using the E.164 format

Bug 22594: Validate SMS messaging numbers using the E.164 format

Many SMS messaging services reject numbers that do not conform to the E.164 international public telecommunication
numbering plan.

We already tell patrons on the OPAC "Please enter numbers only. (123) 456-7890 would be entered as 1234567890."
but we do not enforce this. We should be validating the patron's SMS number on both the staff side and the patron
self-service for updating the SMS number.

Test plan:
1) Apply this patch
2) Enable SMS message ( you can set to Email to enable )
3) Test entering and updating SMS numbers on the OPAC and staff
   interfaces.
4) Note you can only enter a 1 to 14 digit number with an optional + sign
   at the beginning ( used to indicate the number includes a country calling code )

Signed-off-by: Liz Rea <wizzyrea@gmail.com>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>