refactoring plan about improve the respond ability

[dannypsnl]

Is your feature request related to a problem? Please describe. The thread by default created with current-thread-custodian, which will slow down the whole DrRacket, particular if I'm working on some large project (not really large in normal scale, but racket level large).

The fundamental problem is https://github.com/dannypsnl/sauron/blob/fb2eaa94ca305371088f93cb8b9828b690de5f86/collect/record-maintainer.rkt#L79, this collect-from is computation intensive operation, move it into a place worker seems reasonable.

Describe the solution you'd like

1. Make a place module
2. Create 4 workers via place module, and collect-from will be invoked via worker
3. When worker complete the job, send a message back
4. main-thread needs to forward result to correct record-maintainer

Describe alternatives you've considered No idea

Additional context

I found (place-message-allowed? (make-record)) is #f, the reason are fields that involve (make-interval-map).