Add mostly-unchanged Helm chart from k8s-at-home

- Add the chart from k8s-at-home with some modifications
- Add the Apache 2.0 license to the new charts/paperless-ngx
  subdirectory, the license under which the chart was distributed by
  k8s-at-home. I believe the chart will have to maintain this license.

- Update the maintainers section and contact information to point to
  Paperless-ngx.
- Regenerate the README (using helm-docs)

- Add a GitHub actions configuration to publish the chart using GitHub
  pages. This makes the GitHub Pages page rendered by this repository
  usable as a Helm repository, without affecting potential future uses
  of the Pages site.

These are in response to discussion #1790.

charts/paperless-ngx/ci/ct-values.yaml

@@ -0,0 +1,26 @@
+env:
+  PAPERLESS_REDIS: redis://paperless-redis-headless:6379
+
+persistence:
+  data:
+    enabled: true
+    type: emptyDir
+  media:
+    enabled: true
+    type: emptyDir
+  consume:
+    enabled: true
+    type: emptyDir
+  export:
+    enabled: true
+    type: emptyDir
+
+redis:
+  enabled: true
+  architecture: standalone
+  auth:
+    enabled: false
+  master:
+    persistence:
+      enabled: false
+  fullnameOverride: paperless-redis