QNetworkProxyFactory::systemProxyForQuery() implementation for Symbian

Implement a qnetworkproxy_symbian.cpp that can retrieve the Symbian system proxy (e.g. system wide or PAC or ...).

From a mail:

The proxy server details are stored in commsdat, and are roughly:

• IAP ID
• use proxy server - yes/no
• server name
• protocol name
• port number
• list of exceptions (sites)

The code to read commsdat (Symbian comms repository) is truly, utterly horrible, so I would recommend poaching it from somewhere else (eg. the Symbian HTTP stack) - I can provide pointers if necessary. There's no PAC support (at the commsdat level, I don't know if the browser supports reading a PAC file and configuring the proxy settings itself).

The first step to implementing this will be working out how to find the underlying IAP ID for the connection that's in use. I haven't looked at where we need to read this information from, or what state the connection would be in - is there a way to get this out of the Qt bearer management backend? If so, creating the code to set the proxy information shouldn't be too hard.