Allow to configure forward proxy of dbb proxy

[mdutoo]

When EasySOA is installed in a company where an HTTP proxy has already to be used in order to go on the web, merely replacing the web browser's company proxy by EasySOA's is not enough : the DBB proxy should be able to be configured to use the company proxy.

[mdutoo]

Just committed (9e7c67d724b3f1a3c72abe20c56d40ed080ac8b2) a solution (and some bug patches) : configure it in dbb's js/settings.js as said in [doc]().

Closing for now, but still TODO LATER

• PAC (Proxy Auto Configuration .pac file i.e. "proxy auto configuration URL" in browsers) : actually, a PAC file is merely Javascript containing a function FindProxyForURL. So for now, download and open this PAC file to see which to which actual host & port of the company proxy it forwards (see examples) and use them to configure DBB as said.
• HTTPS proxy