Remove old properties, add 4.x properties and metrics

[dlmarion]

Removed 2.x and 3.x properties from the docs-4 directory, added updated property and metrics files generated with apache/accumulo#5495

[ctubbsii]

These should be generated files, and it's draft docs. Probably don't need to do a PR for these. But, I did notice you changed the filenames, and that doesn't correspond to what the build generates (at least, not yet)

[ctubbsii]

The build hard-codes the generated filename as server-properties3.md right now. The build would need to be updated if we're going to go with a different name. This was only changed to add the number for the old docs, because version 2 and 3 were put in the same place. It looks like this won't be the case, given that you've copied all the docs to a different path. So, could go back to the filename without the number on the end.

This same comment applies to the generated metrics and client-properties docs.

[ctubbsii]

Ignore my comments... I see the linked PR to the main branch now. Just merge them both.