Upgrade eslint to v9

Closes #1198

Changes proposed in this pull request:

I would propose to just update eslint and test if everything works properly. I would prefer to handle prettier in a separate PR.

How to test:

This should be tested from the frontend folder. You need node v20+ in order to perfom these tests.
If you have old node modules remove these: rm -rf node_modules
Install dependencies npm install
run linter npm run lint
No errors should be found.
Now add console.log in any of the frontend files and run linter again
It should warn for console logs.
run tests npm test. All test should pass
run build npm run build. Build should work.
run complete RSD setup, make start, RSD should work without problems.

PR Checklist:

research-software-directory / RSD-as-a-service