Git push option to create suggestions and comments
### Problem to solve
When I'm reviewing or testing a merge request locally and spot something that should be changed, I'm often hesitant to make the change and commit it because it might come off as aggressive, but I do want to suggest a change or leave a comment.
Building on top of https://gitlab.com/gitlab-org/gitlab-ce/issues/18008, GitLab should support proposing changes by using a suggestion push option: `git push -o suggestion`
### Further details
This could also address challenges of certain automation tasks like image compression in a CI job that should probably be reviewed by a human. That is a human needs to validate if a screenshot can actually be reduced to a color depth of 32.
### Proposal
Add support for proposing changes by `git push -o suggestion`
Each chunk should be treated as a separate suggestion, and the commit message should be used as the comment above the suggestion.
### What does success look like, and how can we measure that?
Count the number of times suggestions are created with a git push.
### Links / references
issue