Bug 991573 - Copy improvements in Call Barring service through MMI

I asked here at TEF and they pointed me to this standard [1]. I'm going to reference the standard in the comment and explain a bit better what is about this constants.
The bug talked only about changing the text for interrogation of call barring (code \*\#33#). After one of the comments from @gabrielesvelto, I added also interrogation of call waiting (code \*\#43#) because they both work exactly the same, share the same javascript code and display the same message to the user, so makes sense to do the same for both.
There are other interrogation codes, but they display different messages to the user.

[1] http://www.etsi.org/deliver/etsi_ts/122000_122099/122030/10.00.00_60/ts_122030v100000p.pdf