Allow any keys in the overriding values but ensure CRD fields have priority

Currently, the units, k8s_version_short or cluster key words are forbidden in the overriding values

• This is inconsistent wit the fact that they can be used in the valuesFrom ConfigMaps or Secrets
• This prevent some scenarios where units values should be passed

The proposition is to

• Remove VAP policies
• Ensure values generated from CRD fields have the top priority in the values / valuesFrom merging