server name must be validated

[rokroskar]

"FieldValueInvalid","message":"Invalid value: \"renku-jupyter-rok-2eroskar-rok.roskar-proj-85a5229\": a DNS-1123 label must consist of lower case alphanumeric characters or '-', and must start and end with an alphanumeric character (e.g. 'my-name',  or '123-abc', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?')"

Also, since username might be firstname.lastname, 29 characters is likely not enough so need to rethink the pod name template.

[rokroskar]

This is still not solved -- the escaped server names seem to get garbled and cause the volume claims to not be found. Should create tests in the new renku-notebooks repo for this.