REFACTOR(vault): remove Vault database and user

- Vault uses file storage instead
- Remove database dependencies

postgresql/manifests/vault-database.yaml

@@ -1,11 +0,0 @@
-apiVersion: postgresql.cnpg.io/v1
-kind: Database
-metadata:
-  name: vault
-  namespace: postgresql
-spec:
-  cluster:
-    name: postgresql
-  name: vault
-  owner: vault
-  ensure: present