add warning that the cicd docs are incomplete

[finkandreas]

Since some people are sharing the link to the new docs for CI/CD, I've added a warning at the top, that they have not been fully ported.

[github-actions]

preview available: https://docs.tds.cscs.ch/109

[msimberg]

I don't mind adding specific warnings, but just in case you missed it there's a blanket warning for exactly this at the top of every page:

cscs-docs/overrides/main.html

Lines 5 to 12 in b38dea7

	<p>
	Work in progress.
	</p>
	<p>
	The information found here is up to date but incomplete. Many pages are still empty or missing.
	Please refer to <a href="https://docs.cscs.ch">docs.cscs.ch</a> for documentation missing from this site for the time being.
	</p>

. Would you like to add the specific warning despite that?

[finkandreas]

Yeah, the blanket warning on a black background fades away in my normal view. With the current status (and given that the CI/CD docs look "long"), one could think that CI/CD is already fully ported. I just want to make sure, people are aware that there's still more docs at the old space.