core: remove commons httpclient from provider proxy

As commons-http client is no longer maintained, there are
two options -
a. move to httpcomponents which is maintained,
b. have our own implementation for httpclient.
As our requirements from http clients are quite minimal,
I have selected option b.
This patch addresses the foreman provider proxy as it uses SSL based
communication.
VdsBroker will eventually contain only the JSON RPC communication

Change-Id: I727d34c33f357b93560d4b5a1784b3733b7fa293
Signed-off-by: Yair Zaslavsky <yzaslavs@redhat.com>