[JBIDE-15146] corrected IHttpClient#STATUS_INTERNAL_SERVER_ERROR
[JBIDE-15193] fixed message assert to accept new broker behaviour
[JBIDE-14366] Adding timeout to request methods
[JBIDE-15115] implemented IOpenShiftResource#getMessages()

Implemented IOpenShiftResource#getMessages() and a Messages class in
order to hide internal Multimap structure required with new way of
reporting creation log/messages.
Also turned Severity into a class so that it gets extensible and allows
us to report unknown severties