Enable local persistence of detected schemas

## Is your feature request related to a problem? Please describe.

I'd like to be able to save the detected schema locally. The schema information could then be restored later without needing another schema detection.

There are some collections that we work with that are very large and we may need to sample many or all of the documents. Minimizing the number of times that we do schema detection is important.

## Describe the solution you'd like

Hooks in the driver for:
- Persisting the schema of a collection
- Restoring the persisted schema of a collection (to skip schema auto detection)

## Describe alternatives you've considered

None

## Additional context

At this point I'm most curious about the feasibility of this feature. Is it possible? How big of a change would this require?

Start by reviewing the driver's schema-detection flow and the open pull request #477. Determine how collection schemas are represented and where persistence and restoration hooks would fit; done means a schema can be saved locally and restored to skip repeated detection.

Written by the indexing model from the issue text.