gotenberg: seccompProfile RuntimeDefault in the pod context

Sets seccompProfile.type: RuntimeDefault in the pod security context, so
the container runtime's default syscall filter applies to every container
in the pod.

The value lives in the pod context rather than the container context
because it covers init containers and any container added later without
being repeated; a container that needs a different filter can still
override it under securityContext.container, which wins over the pod
value.

Gotenberg is the chart where a syscall filter was most likely to bite: it
drives headless Chromium and LibreOffice, and browser sandboxes are the
classic casualty of a restrictive seccomp profile. Verified in k3d that
both engines still work under the filter - Chromium HTML->PDF and
LibreOffice document->PDF both return real, non-empty PDFs, and the
kernel reports Seccomp: 2 (filter mode) inside the container.

Major bump: runtime behavior changes.

Refs #84

gotenberg/templates/_helpers.tpl

@@ -214,7 +214,8 @@ rebuilt default probe needs no further context.
 {{- $defaults := dict
       "runAsNonRoot" true
       "runAsUser" 1001
-      "runAsGroup" 1001 -}}
+      "runAsGroup" 1001
+      "seccompProfile" (dict "type" "RuntimeDefault") -}}
 {{- include "gotenberg.defaultedDict" (dict "defaults" $defaults "given" $given "path" "gotenberg.securityContext.pod") -}}
 {{- end -}}