util: make parseTenantConfig() usable for modular KMSs

parseTenantConfig() only allowed configuring a defined set of options,
and KMSs were not able to re-use the implementation. Now, the function
parses the ConfigMap from the Tenants Namespace and returns a map with
options that the KMS supports.

The map that parseTenantConfig() returns can be inspected by the KMS,
and applied to the vaultTenantConnection type by calling parseConfig().

Signed-off-by: Niels de Vos <ndevos@redhat.com>

examples/kms/vault/tenant-sa-admin.yaml

@@ -82,7 +82,7 @@ spec:
             - name: K8S_HOST
               value: https://kubernetes.default.svc.cluster.local
             - name: PLUGIN_ROLE
-              value: csi-kubernetes
+              value: ceph-csi-tenant
             - name: TENANT_SA_NAME
               value: ceph-csi-vault-sa
             - name: TENANT_NAMESPACE

examples/kms/vault/tenant-sa.yaml

@@ -20,3 +20,4 @@ metadata:
   name: ceph-csi-kms-config
 data:
   vaultBackendPath: tenant
+  vaultRole: ceph-csi-tenant