Automatically generate CE/EE diff after each upstream MR

I've created a script to generate the diff given a CE commit, an EE commit, a EE repo path, a date, and the URL of the Upstream MR.

The script and the CE/EE diff created after each run of the script can be found at: https://gitlab.com/rymai-gitlab/ce_ee_diffs_generator/tree/master/diffs

TODO:

Find a good name
Automatize the diff creation after a CE upstream MR is merged (could be in the same project as #25932 (closed)).
Move the project to gitlab-org