Merge this repo into a "website" repo

[benjub]

It looks like it would be more convenient and would reduce complexity to merge

• https://github.com/metamath/metamath-website-scripts
• https://github.com/metamath/metamath-website-seed
• https://github.com/metamath/symbols

into a single repository metamath/website, and it would also centralize issues and pull requests.

As for metamath/symbols, note that it is currently not a standalone repo, see metamath/symbols#1 (comment). As for the renaming itself, see https://docs.github.com/en/repositories/creating-and-managing-repositories/renaming-a-repository.

[GinoGiotto]

I agree with this proposal.