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

template-chart/templates/xxx.configmap.yaml

@@ -1,6 +1,6 @@
 apiVersion: v1
 kind: ConfigMap
 metadata:
-  name: "{{ .Release.Name }}-{{ .Chart.Name}}-config-map"
+  name: "{{ .Release.Name }}-{{ .Chart.Name }}-configmap"
 data:
   key: "value"