authelia: Install Authelia

Authelia is a general authentication provider that works (primarily)
by integrating with *nginx* using its subrequest mechanism.  It works
great with Kubernetes/*ingress-nginx* to provide authentication for
services running in the cluster, especially those that do not provide
their own authentication system.

Authelia needs a database to store session data.  It supports various
engines, but since we're only running a very small instance with no real
need for HA, SQLite on a Longhorn persistent volume is sufficient.

Configuration is done mostly through a YAML document, although some
secret values are stored in separate files, which are pointed to by
environment variables.

authelia/kustomization.yaml

@@ -0,0 +1,24 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+- authelia.yaml
+
+configMapGenerator:
+- name: authelia
+  namespace: authelia
+  files:
+  - configuration.yml
+  options:
+    disableNameSuffixHash: true
+
+secretGenerator:
+- name: authelia
+  namespace: authelia
+  files:
+  - jwt.secret
+  - ldap.password
+  - session.secret
+  - storage.encryption_key
+  options:
+    disableNameSuffixHash: true