Remove HTCondor-CE documentation duplication
Upstream's documentation is based upon ours and generally more up-to-date. Let's trim down our doc footprint and lean on upstream (https://htcondor.github.io/htcondor-ce/). We should be able to do this for:
For these documents replace their contents entirely with a message saying that up-to-date documentation can be found at . Then remove each document from mkdocs.yml so that they’re still built (and accessible) but not visible in the TOC
Additionally, remove from the ToC and add a !!! info admonition explaining that COVID-19 jobs are no longer prioritized and that the documentation is deprecated.