Improve nightly build notifications and ids

[bendnorman]

While debugging a recently nightly build failure, we ran into a few issues:

1. Notifications from dev and tag builds are mixed together in our pudl-deployments slack channel which caused confusion around which logs to look at. Instead we should have a thread for each build so the sequence of messages for builds don't get mixed together.
2. We should make our build ids more human readable to it's easier to find logs and outputs. Currently its gitsha-branch but it could be something like YYYY-MM-DD-{config}-{sha}-{branch}.
3. The nightly-build-output.catalyst.coop bucket contains assets from our nightly dev builds, our manually triggered branch and tag builds. We should probably rename the bucket to be more general. Something like pudl-builds.catalyst.coop.