satisfactory chart: naming scheme, security hardening, configurable probes

All audit findings from #32 for the satisfactory chart in one major PR:

- StatefulSet renamed to {{ .Release.Name }}-{{ .Chart.Name }}-sfs, service
  to ...-service (standard scheme); template file satisfactory-server.sfs.yaml
  renamed to satisfactory.sfs.yaml. The PVC keeps its historical -vc name
  (documented naming exception; renaming would orphan the data).
- Hardened, values-configurable security contexts (securityContext.pod /
  securityContext.container): runAsNonRoot with the image's steam user
  (uid/gid 1000), readOnlyRootFilesystem, all capabilities dropped. emptyDirs
  mounted at /tmp and the steam user's ~/.steam, ~/.config and ~/.local make
  the read-only root filesystem work; all other writes go to the PVC.
- Probes are now values (livenessProbe/readinessProbe/startupProbe), defaults
  exactly the previously hardcoded values.
- Additive env value rendered through tpl with value/secretKeyRef/
  configMapKeyRef forms (template-chart pattern).

Chart 3.1.1+upv1.9.10 -> 4.0.0+upv1.9.10 (major: resource renames +
hardening); appVersion unchanged.

satisfactory/Chart.yaml

@@ -3,7 +3,7 @@ name: satisfactory
 description: A Helm chart to deploy a Satisfactory Gameserver on Kubernetes
 icon: https://raw.githubusercontent.com/wolveix/satisfactory-server/main/.github/logo.png
 type: application
-version: 3.1.1+upv1.9.10
+version: 4.0.0+upv1.9.10
 appVersion: "v1.9.10"
 maintainers:
   - name: jklein