chore(docker): update & simplify docker mysql setup

[marcelgerber]

I noticed that we're using an outdated Docker image (mysql-server) that hasn't been updated for two years.
mysql is now the official and recommended image, and unlike a few years ago it now also has a release for ARM Macs.

So, we're now using mysql:8, which currently points to 8.4.
It may make sense to update to mysql:9 at some point, however we can only upgrade the DB in-place from a LTS release, which we are not currently on. Also, this would entail updating our prod servers, so...

While playing around with this stuff, I also noticed that the custom mysql-init-docker container we are creating is entirely unnecessary: all the cli tools we need to run the update script (mostly just gunzip and a few other basics) are already part of the mysql:8 installation. Which means, we can now just use the mysql:8 image instead :)

For review purposes: You can go by commits here, they are self-contained.

Things I tested:

• ✅ Running in a new repo: It properly downloads and fills the DB, and the admin server starts up
• ✅ Running in an existing repo: It properly upgrades the DB file in-place.
• ✅ DB tests run fine

[owidbot]

Quick links (staging server):

Site Dev	Site Preview	Admin	Wizard	Docs

Login: ssh owid@staging-site-mysql-docker

• Site-screenshots: https://github.com/owid/site-screenshots/compare/mysql-docker
• SVG tester: https://github.com/owid/owid-grapher-svgs/compare/mysql-docker

SVG tester:

Number of differences (default views): 0 ✅
Number of differences (all views): 0 ✅

Edited: 2025-02-17 09:45:36 UTC
Execution time: 1.25 seconds

[Marigold]

Tested it locally and everything worked as expected. Nice cleanup!

[danyx23]

I haven't played with it but it all looks fine - thanks for the cleanup!