[openstack-helm] Cleanup OSH ingress chart

Hi dear colleagues,

Some time ago we switched all our test deployment jobs to using the upstream Ingress-nginx chart. So it looks like we can recommend using one of the third party ingress controller charts to all our users. The deployment requirements for third party ingress controllers like ingress class name and ingress pod labels are described in the documentation [1] and this script [2] can be used as an example.

I suggest removing the OSH ingress chart to reduce the code base that we need to support. Opinions are very welcome.

[1] https://docs.openstack.org/openstack-helm/latest/install/deploy_ingress_cont... [2] https://opendev.org/openstack/openstack-helm/src/branch/master/tools/deploym...