BUG-2511 Fix XXE vulnerability in initial config loaders

Change-Id: I0b9aefa8d7a2d59f542075172fe03678618a6385
Signed-off-by: Maros Marsalek <mmarsale@cisco.com>
Fix bug 2449 in sal-remoterpc-connector
Regarding to Moiz's comments, replace sender from null to
ActorRef.noSender() in RpcManager.java

Register SchemeContextListener with global SchemeService and push scheme
context to RpcBroker

Change-Id: Ia941f25f7b82a8146bf412389fbea5219c76f55a
Signed-off-by: Xin Chang <xin.chang@huawei.com>
Merge "Fix bug 2449 in sal-remoterpc-connector Regarding to Moiz's comments, replace sender from null to ActorRef.noSender() in RpcManager.java" into stable/helium