Simplify helm chart by resolving ingress controller as an external dependency

[kalinkostashki]

Currently we have the nginx-ingress controller which does its job well, but there is some overhead introduced there. They idea of having all its necessary resources as templates maybe wasn't optimal.

I would like to suggest that we move on to the official nginx-ingress charts as a dependency. That way we could only rework the values.yaml to coform to the requirements of that helm chart and remove manual resources we are currently supporting :)

[thjaeckle]

Sounds good 👍