Highlight negative and positive coverage changes in merge requests

Description

In merge requests you can currently see the new coverage in percent after a coverage pipeline job succeeded. It would be more helpful if you can see the coverage change: If it got improved or if it changed for the worse.

Proposal

There should be something like a red or green badge and a text like

• "Coverage improved from 13.37% to 42.00%"
• "Coverage changed from 42.00% to 13.37%"

Links / references

Old:

New: