Add ability to show custom values in gitlab build status and build log

Description

I recently discovered <project>/pipelines/settings has the ability to populate the code coverage from a build result. Code coverage is a good overall thing to keep track of, but in several of my projects I also need to keep track of other metadata like warning count.

Proposal

Add dynamics fields that can be populated with user defined data from a build result. These dynamic fields will be shown in the build status and the build log views. These field names and values can be defined through a project setting like with code coverage, or directly through the .gitlab-ci.yml.

Links / references

I made a small example of how it could look below. I'm no graphic designer, but I think this gets the point across.