Add a simple way in MRs to view diff evolution over time

[roblabla]

Currently, each commit gets a "compare" CI check that shows the diff score of every implemented function when compared against the official binary. However, the only way to see how a given PR influences the diff score is to manually check it against master. That's unfortunate and error prone.

We should be able to add an extra step to the compare stage that adds a message to the PR showing what exactly changed.