Vault policy generation

The idea is to describe vault policies for users here because keycloak roles need to be mapped to vault groups and policies. Managing them in the same repo should avoid desynchronization between actual roles and policies definitions. Like keycloak ressources it generates a module containing generated vault resources. This module can be sourced in a terraform stack.

Vault policies are directly written in cue in the file vault.cue. This allows the use of powerful templating techniques in cue.

Vault policies are associated to roles. Thanks to cue only the content of the policy needs to be described as the associated group ressources are generated automatically based on the name of the policy