The following patch intoduce the dictionaries pre and postExtraInitContainers.
The dictionaries can be used to specify further initContainers before and after
the gitea initializing process. For example:
```yaml
postExtraInitContainers:
- name: foo
image: docker.io/library/busybox:latest
preExtraInitContainers:
- name: bar
image: docker.io/library/busybox:latest
```
