Conventions batch 1: icons, template file names, cosmetics

- Add icon: to all 17 Chart.yaml (official project icons); removes the
  last helm lint --strict INFO finding across the repo
- Rename template files to the <app>.<kind>.yaml scheme (apache-tika,
  gotenberg, teamspeak-server PVC, paperless-ngx configmap) - pure
  git mv, no content changes
- template-chart: fix missing space in {{ .Chart.Name}} and rename the
  ConfigMap resource -config-map -> -configmap (chart is never published)
- rallly: fix typos in required messages (rallySecret -> ralllySecret,
  databseSecret -> databaseSecret)
- README: document the deliberate PVC-name exception from the naming
  scheme (renames would provision new empty volumes)
- Patch-bump all 16 published charts

Rendered resources are byte-identical for all published charts (only
helm's '# Source:' comments change for the renamed files); the only
render change is the template-chart ConfigMap name.

Part of #32

urlaubsverwaltung/Chart.yaml

@@ -1,7 +1,8 @@
 apiVersion: v2
 name: urlaubsverwaltung
 description: A Helm chart to deploy urlaubsverwaltung on Kubernetes
+icon: https://raw.githubusercontent.com/urlaubsverwaltung/urlaubsverwaltung/main/src/main/resources/static/favicons/apple-touch-icon.png
 type: application
 
-version: 4.1.1+up6.7.0
+version: 4.1.2+up6.7.0
 appVersion: 6.7.0