[ENHANCEMENT] Force identity.auth.enable:true when multinenancy.enable:true

[pierre-yves-monnet]

Describe the use case:
When the user moves the cluster to a multi-tenancy, it must set the authentication to true.
Otherwise, we have a cluster in a terra incognita world, and logging/error does not help to figure out what the issue is.

Describe the enhancement/feature:

When values.yaml give
multinenancy.enable:true
then automatically, the helm chart force
identity.auth.enable:true

Desired outcome and acceptance tests:

[aabouzaid]

@pierre-yves-monnet Thanks for reporting that 🙌
We avoid manipulating user input so I've added it to the constraints to fail the installation with a message with instructions to enable the requirements.