Support update operations #69
Description
Currently, when a Service Entry is updated we delete the "previous version" of it from the SDWAN and re-create it once deletion finishes.
This is fine and easy to implement/understand, but can certainly be improved. The egress watcher will be updated to also support update operations "natively" -- i.e. with PUT operations, whenever feasible.
This should also lower the time it takes SDWAN to apply configuration by ~50% as we don't apply it twice (once to delete it and once to re-create it)