Clean-up the repo's git history to reduce its size

[DominiqueMakowski]

Because we have added and then removed large files every now and then (data), the git history is huge and it takes forever to fork the repo. How can we clean the history a bit while not removing anything important 🤔

https://stackoverflow.com/a/60036346/4198688 https://github.com/newren/git-filter-repo/blob/main/README.md

Problem is; I am totally unfamiliar with git commands. Any help on that front would be welcome!