Option to set .gitlab-ci.yml's Parsed YAML Size Limit
### Update
The problem in this issue has been addressed in https://gitlab.com/gitlab-org/gitlab/-/merge_requests/68593/diffs#1765cf44c27db7ec15366f9596a103f0c92fe457+ for self managed new issue created to consider increasing the default CI YAML limits. https://gitlab.com/gitlab-org/gitlab/-/issues/370116
### Problem to solve
Gitlab 12+'s
```
The parsed YAML is too big
```
### Intended users
Administrators who have enough resources that the size of the parsed YAML doesn't matter.
### Further details
We recently upgraded to 12.0.3 (gitlab-ce@08a51a9db938bb05f9a4c999075d010079e16bad) and to our surprise our big project's `.gitlab-ci.yml` stoped parsing. In lieu of support to specify a cartesian product (gitlab-ce#19199), we wrote a script to take all our unit tests and create jobs to run for each platform we are supporting. This generates a very large CI file, and up until version 12 GitLab has happily chugged along without a hitch.
### Proposal
Create a "Maximum .gitlab-ci.yml Parsed Size" option in the "CI/CD Admin Area", just like the "Maximum Artifacts Size" setting.
### Permissions and Security
The administrator with access to the "CI/CD Admin Area".
### Documentation
Not sure what to put here, sorry.
### Testing
Once again not sure what to say here. IMO it would improve the product by allowing local administrators to control GitLab in their environment.
### What does success look like, and how can we measure that?
Just as success was measured for the "Maximum Artifacts Size". Does GitLab provide flexibility to its Administrative users?
issue