Update common workflows functions, add readiness loop

The function check_workflow_status was updated to use retries rather
than time. In addition, a new generic function was created to evaluate
the readiness of Kubernetes objects in a loop.

Change-Id: I7e7268ecb0809ebe8895720fbfbd1c39138fd87f
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>