Update paperless-ngx to version 0.25.4 and add probes

This commit updates the paperless-ngx Helm chart to version
0.25.4, reflecting the latest version in Chart.yaml and in
the README.md badge. The homepage URL has been changed to
point to the new repository location.

Additionally, liveness and readiness probes have been added
to the values.yaml configuration. These probes utilize curl
to check the application's health on localhost:8000, ensuring
better handling of container lifecycles.

The readiness probe starts after a 60-second delay, while
the liveness probe has a longer delay of 120 seconds, helping
to manage startup times effectively.

No breaking changes are introduced, but users should review
the new probes configuration for their deployments.

charts/paperless-ngx/Chart.yaml

@@ -4,7 +4,7 @@ description: "A community-supported supercharged version of paperless: scan, ind
 home: https://charts.gabe565.com/charts/paperless-ngx/
 icon: https://raw.githubusercontent.com/paperless-ngx/paperless-ngx/b948750/src-ui/src/assets/logo-notext.svg
 type: application
-version: 0.25.3
+version: 0.25.4
 # renovate datasource=docker depName=ghcr.io/paperless-ngx/paperless-ngx
 appVersion: 2.20.0
 kubeVersion: ">=1.28.0-0"