Add admin ingress to expose it externally

[mkocsis-tg]

Add new Kind: Ingress for the admin API calls. This is a convenience feature to expose the admin API. This would enable the access to it form outside of the cluster.

Reasons: support configuration as code setup via curl / ansible or any other provisioning tools over http / https through the admin REST api.

[tokers]

This is convenience but it's dangerous if you expose the CP through the DP.

[mkocsis-tg]

That is why it is disabled by default int he PR