chore: Some tests while upgrading

[munen]

@schoettl I tried to work off your PR and maybe get to the next step. There's a lot of upgrading at the same time, though^^

Some things I did:

• Follow the advise in: "process" (and all env vars) not available after upgrade from 4.0.3 to 5.0.1 facebook/create-react-app#12354 (comment) by working off this tutorial.
  • Result: I reverted back. After some work, I got organice to 'run' with Vite. However, it was only a white screen. So I reverted.
• I kind of followed your lead by going back to the latest react-scripts@4 and eslint@7. But then I still had to do some things to get yarn start to run:
  • Pin babel/core. Otherwise a transient dependency of react-scripts will complain.
  • Install sass. I see you removed node-sass, but we still need some sass compilation.
• Revert the upgrade of date-fns. I'm generally in favor of the upgrade, but there was more to change and I wasn't able to. There's some 'chaining' happening which would require new babel plugins. I tried, but failed. So I opted for the revert.

Now, yarn start kind of works. I see no error in the console and I can use organice. But there's still a lot of work left. For example there's an error in yarn test and yarn build won't work at all.

I'll leave my changes in this PR in case you want to use them.