Various fixes for the refactored workflows

[HebaruSan]

Problems

• Dev builds are currently broken because the version.json file from Support dev builds for auto updater #3997 isn't being generated anymore. I assume Refactor + Modernise Actions #4082 removed this because of some sort of Python dependency issues in the newer containers, but we still need it.
• upload-nuget in release.yml was trying to download a Release-repack-out artifact that doesn't exist (it's just Release-out)
• Several steps have incorrect names ("stable" instead of "nightly", "deb" instead of "ckan.exe and netkan.exe", etc.)
  • Many other steps have no names at all, and in a few places this makes the logs less clear (e.g., two consecutive steps with the same default name)
  • Still other steps have names that could be slightly clearer (e.g., "Upload XYZ release asset" instead of just "Upload XYZ" in a workflow that uploads lots of stuff to lots of places, or specifying which artifact we're downloading to make it easier to track what's happening)
• upload-release-s3 in deploy.yml tightly couples checking for odd builds with a job that doesn't even need that, which should be done in a shorter, standalone job
• The Credentials step of deploy.yml is weird. I cannot figure out what it's supposed to be doing. It sets a credentials output to false if the credentials do exist, whereas that name suggests to me it would be true if the credentials exist and false if they don't. But if the credentials don't exist, then the credentials output isn't set at all, which still means false in workflow expression syntax! So the meaning and purpose of the credentials output is very unclear. It is used as a condition in a couple of other jobs that somehow always run even though they depend on an output that's always false.

Changes

• version.json is once again created and uploaded to S3. I'm expecting this to fail due to Python's extreme environmental sensitivity, but I'll fight with deploy.yml about it after merge.
• Since we are hoping to sign the NuGet package, the current Release-out and Debug-out artifacts are renamed Release-out-unsigned and Debug-out-unsigned.
• The odd-build output is renamed dev-build and is now generated by a smaller, simpler check-dev-build job with no side effects. Jobs that need this info are updated to needs this job instead of upload-release-s3.
• The credentials output stuff is removed, and the aws-actions/configure-aws-credentials steps are moved to be the first in their jobs so if the credentials are missing, the job stops early. If there's a reason why it was like that, then I'll find out what it was after merge.