Update carrier info for giffgaff

[davwheat]

I'm not sure if this is the place to add issues but I couldn't find anywhere else easily.

These are the correct values for giffgaff. They're incorrect in AOSP but they only accept APN edits from carrier employees themselves.

These are combined MMS and GPRS settings so separate entries aren't required.

Field Name	Field Value
Connection Name	giffgaff
APN	giffgaff.com
Proxy	[leave blank]
Port	[leave blank]
Username	giffgaff
Password	[leave blank]
Server	http://mmsc.mediamessaging.co.uk:8002
MMSC	http://mmsc.mediamessaging.co.uk:8002
MMS proxy	82.132.254.1
MMS port	8080
MCC	234
MNC	10
Authentication Type	PAP or CHAP
APN type	default,supl,mms,ia,xcap
APN protocol	IPv4
APN roaming protocol	IPv4
Bearer	[leave blank]