Render Markdown in blurbs.

[antarcticrainforest]

Because of security concerns only pure text strings were allowed in the home pages blurbs.

This PR enables Markdown based rendering allowing for a minimal set of slightly more elaborate text rendering while trying to keep the system safe.

Displaying external links, line breaks, bold, recursive is now supported via simple markdown text.

@eelucio FYI, @Karinon I hope this doesn't affect your security concerns.

[BiancaWentzel]

For me it looks fine but maybe I am not aware of security issues arising from this change

[Karinon]

I am not going to test it locally, but I think this is fine so far.

[eelucio]

I did not run it locally yet (still installing stuff), I have no opiinion about security stuff, two minor things:

• release/version metadata is inconsistent across the branch. package.json (line 3) bumps the app to 2606.0.1, but CHANGELOG.md (line 4) adds the new entry under v2606.0.0 and package-lock.json (line 2) still says 2605.2.2. That makes the release history ambiguous and leaves npm metadata out of sync.
• apparently there are still some legacy references to FrevaGPT instead of climateclaw (but I guess that these being internal functions does not amtter)

[antarcticrainforest]

I did not run it locally yet (still installing stuff), I have no opiinion about security stuff, two minor things:

* release/version metadata is inconsistent across the branch. package.json (line 3) bumps the app to 2606.0.1, but CHANGELOG.md (line 4) adds the new entry under v2606.0.0 and package-lock.json (line 2) still says 2605.2.2. That makes the release history ambiguous and leaves npm metadata out of sync.

* apparently there are still some legacy references to FrevaGPT instead of climateclaw (but I guess that these being internal functions does not amtter)

Thanks for the hints, I've updated them now. I also replaces npm install by npm ci which wuould make the command fail package.json and package-lock.json are out of sync.

[antarcticrainforest]

https://eve.dkrz.de has those changes rendered.