Update CSS to version 6, update ESLint configs and add Node 18 to CI

[surilindur]

The main goal here was to bump the Community Solid Server dependency to version 6, because it was stuck on 5 and 6 has been out for a while now. The latest version of the CSS also allows .meta files with FixedContentTypeMapper, which makes it possible to add triples to containers themselves for benchmarking purposes. I have adjusted the server configuration in templates to work with the new CSS version.

The other changes in this PR that I wanted to have feedback on (making it a draft) are the following:

• Updating @rubensworks/eslint-config to version 2, and removing the dependencies from here that are provided by that package already. Three rules had to be disabled in .eslintrc.js after this, but otherwise it seemed to just work.
• Setting rimraf to use an actual version rather than latest, because the tag was causing some warnings about unpack paths and something being skipped with Yarn version 1.
• Adding Node 18.x to the CI
• Adding --ignore-engines to avoid 'package not compatible with Node version' errors
• Adding --frozen-lockfile to make sure the CI installs exactly what is in the lockfile.

Any feedback is welcome. I can also remove changes if some of them seem dubious. :slightly_smiling_face:

[surilindur]

Yes, the server works still. I ran the generate and serve commands locally after the changes and both worked. Generating the validation things did not work, but it also did not work before the changes (it produces a JSON-like error about something query-related).

Thank you for the feedback!

[coveralls]

Pull Request Test Coverage Report for Build 6035257917

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 5529156034:	0.0%
Covered Lines:	116
Relevant Lines:	116

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💛 - Coveralls

[surilindur]

Is it enough to change the Node version requirement in readme to 15? According to the MDN, replaceAll has been in Node since version 15.

[rubensworks]

Let's put 16. Uneven Node versions are considered unstable.

[surilindur]

I have changed the Node requirement to 16. Are there any other things that should preferably be changed before merging?

[rubensworks]

I think Node was it indeed! Is this PR ready for another review? (you can click re-request review on top of this page)

[rubensworks]

Thanks @surilindur! Do you need a new release of this?

[surilindur]

Yes, but not immediately. If there will be a new release at some point within the next month or two that should be enough. It will take me a while to get the code ready for benchmarking.

[rubensworks]

Ok, just ping me as soon as you need it. (unlikely that a new release will show up otherwise)