Package updates

I updated the dependencies in order to get rid of all the vulnerabilities of severity "high" and above (which fixed all of them as a side-effect). It required an update of react-scripts to the next major version which might be a breaking change. I did not do any testing except for running the build. There are several problems which should be checked as part of a review:

• Check that the changes do not break anything.
• Check There was an error trying to load the config "styledComponents" for the macro imported from "styled-components/macro. Please see the error thrown for more information. warnings.
• Check no-unused-vars (and fix the code).

Also, npm outdated still lists several libraries as outdated. All of those change major versions. Please also check if an update is possible/reasonable and add to this MR as required.