Add tigera operator package

[ralgozino]

It would be nice to have a new package in the networking module with the calico-tigera-operator.

This operator would make easier the installation of the networking and could also be a fix to have #38 as just a configuration option instead of having to maintain two different packages.

The migration from the manifests-based deployment to the operator-based one is pretty straightforward according to the official documentation:
https://projectcalico.docs.tigera.io/maintenance/operator-migration