fix: Run ostree container commit at the end of each module run (#103)

Since the command `ostree container commit` checks for the presence of
mounted directories, we will be running it at the end of each module
run. We have also updated the final commit to remove from /tmp/ and
/var/ again in case a user creates extra files through custom
instructions.

Closes #101 #95

template/templates/modules/modules.j2

@@ -20,7 +20,8 @@ RUN \
   --mount=type=bind,from=stage-exports,src=/exports.sh,dst=/tmp/exports.sh \
   --mount=type=cache,dst=/var/cache/rpm-ostree,id=rpm-ostree-cache-{{ recipe.name }}-{{ recipe.image_version }},sharing=locked \
   chmod +x /tmp/modules/{{ type }}/{{ type }}.sh \
-  && source /tmp/exports.sh && /tmp/modules/{{ type }}/{{ type }}.sh '{{ module.print_module_context() }}'
+  && source /tmp/exports.sh && /tmp/modules/{{ type }}/{{ type }}.sh '{{ module.print_module_context() }}' \
+  && ostree container commit
     {%- endif %}
   {%- endif %}
 {%- endfor %}