Use Container Scanning for our GitLab images
### Problem to solve
We create Docker images during our GitLab development in different places:
1. GitLab releases
1. GitLab Review Apps
1. GitLab security features
1. ...
We should use our Container Scanning features to check the security of those images, and figure out if we need to introduce new features to support our internal flow.
### Proposal
- [ ] Check why Container Scanning is not used in our internal projects
- [ ] Improve the feature to support our internal flow, if needed
- [ ] Enable Container Scanning for our internal flow (releases, review apps, security products, etc)
issue