Mark mobility bearer classes as deprecated in the header file

Since developers don't read release notes, but hopefully do pay attention to compiler warnings

Add the QT_DEPRECATED and QT_DEPRECATED_CONSTRUCTOR macros to all functions in the mobility headers for the bearer classes which have been moved into QtNetwork.
On seeing the warning, hopefully developer will read the documentation and see that they need to update their code.
When Qt 4.8 comes along, applications that rely on the Qt Mobility implementations may break because Open C sockets are not used anymore in QtNetwork.

RVCT and GCC both emit warnings when a deprecated function is used