- Request server for alarm_id before creating new one
- Adding http get method to _perform_request of common Sender
- Add unit tests for {aodh,common}/sender
Change-Id: I48e83e87349048962c400a2660cd0c0252563ea0
Closes-bug: #1672296
Signed-off-by: Ivan Dyukov <i.dyukov@samsung.com>