Nuke repository to replay old version on top of here

History of this repository:

1. started at https://github.com/alexpovel/thesis_template/ and was
very rudimentary.

2. moved to https://collaborating.tuhh.de/alex/latex-cookbook and was
completely overhauled there. I used that platform because back then
GitHub didn't offer free CI runners, while our university's GitLab
instance did.

3. moved back to GitHub, at https://github.com/alexpovel/latex-cookbook/
GitHub now has GitHub actions, so we can also do free CI/CD there.

So, the project from 1. was kept alive but archived. After going back
in step 3., I wanted to keep its stars and forks, hence not delete it.
However, the long commit history that resulted in step 2 had to be
kept alive as well, since short-SHA references would be lost upon
rebasing on the repo in 1.
Therefore, I kept the project under 1., nuked it, replayed 2. onto it
(keeping all hashes identical), then moved what used to be the content
of repo 1. into its own branch.

This commit is the start of that branch.