iii 0.21.4-next.2

What's Changed

• docs: complete missed 0.21.x version rotation by @guibeira in #1945
• docs: update configuration management details and add new configuration page by @sergiofilhowz in #1941
• feat(observability): making observability worker a required one by @sergiofilhowz in #1947
• fix(docker): make the engine boot cleanly in Docker (writable /app/config + seed-strip noise) by @guibeira in #1946

Full Changelog: iii/v0.21.3...iii/v0.21.4-next.2