Sets up preview deploys etc. for bemo worker.
There's enough going on here that I wanted to make it its own PR. I'll
rework david's spike on top of it once it's landed.
### Change Type
- [x] `internal` — Does not affect user-facing stuff
- [x] `chore` — Updating dependencies, other boring stuff
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Co-authored-by: David Sheldrick <d.j.sheldrick@gmail.com>
