Provide default outbound proxy configuration

[phax]

Should use the same configuration properties as the other components.

This should be aligned between

• SMP Client (uses http.proxy.host, http.proxy.port, http.proxy.username and http.proxy.password properties)
• Directory Client (for phoss SMP) (uses http.proxy.host, http.proxy.port, http.proxy.username and http.proxy.password properties)
• SML Client (uses the global java.net.ProxySelector implementation)
• phoss SMP (uses http.proxyHost, http.proxyPort, https.proxyHost, https.proxyPort, proxy.username and proxy.password properties)
• phase4 (none so far)