feat: proxies can now be set using HTTPS_PROXY

[quintesse]

For now this simply extracts the host and port from the proxy URL and uses those to connect, just if we were using the RHT_INSIGHTS_JAVA_PROXY_HOST and PORT variables.

This very likely too simple. First I'm not really sure if using RHT_INSIGHTS_JAVA_PROXY_HOST/PORT actually connects using SSL or not and secondly a proxy URL could contain authentication information which we don't use right now.

Fixes MWTELE-42

[quintesse]

@aslicerh in the end I decidede against showing a messages when HTTP_PROXY is set because the class that handles the proxy setup does no logging whatsoever so I wasn't sure it was a good idea to add some. THe other reason is that for the server side it's probably okay to give this warning, most likely you're not running anything else on the server. But for a client library we cannot assume that environment variables are only used for the app we're running in. So giving warnings (or even errors like the server) is probably too restrictive.

[aslicerh]

@aslicerh in the end I decidede against showing a messages when HTTP_PROXY is set because the class that handles the proxy setup does no logging whatsoever so I wasn't sure it was a good idea to add some. THe other reason is that for the server side it's probably okay to give this warning, most likely you're not running anything else on the server. But for a client library we cannot assume that environment variables are only used for the app we're running in. So giving warnings (or even errors like the server) is probably too restrictive.

I think that is a fair assessment.

[aslicerh]

LGTM

Even if this is a first step, we can do more as needed.

[kittylyst]

Please see comments.

[kittylyst]

LGTM