BISERVER-10660 - HttpClient getClient() in HttpUtil.java doesn't support proxy [marketplace]

What was done:
1) added check if proxy is configured
2) changed the way HTTP call is done -- if a proxy is configured -- it
is used
Merge pull request #1400 from kolinus/biserver-10660

BISERVER-10660 - HttpClient getClient() in HttpUtil.java doesn't support...