Code UX improvements

[justheuristic]

Codebase updates

• [x] hivemind.Optimizer docs with tips and examples ready
• [x] quickstart with Optimizer ready
• [x] tweak hivemind logging so that it no longer causes weltschmerz ( https://github.com/learning-at-home/hivemind/pull/418 https://github.com/learning-at-home/hivemind/pull/419 )
• [x] make @borzunov 's intended renames into the dalle repo (e.g. step <=> epoch)
• [x] update hivemind's PyPI so people can use pip install
• [ ] Hide extremely large ETA values
• [ ] Make more hivemind.Optimizer fields public (can be done later)