chore: add BSON doc editor component, use for FLE2-related fields COMPASS-5949

[addaleax]

This partially addresses COMPASS-5949 and might be useful as a starting point for what approach we want to take here.

Currently, this creates a new BSONDocumentEditor component specifically for editor instances that are targeting BSON documents (which most of our editors do), adds an EJSON/Shell syntax switch to it, and centralizes parsing/JS serialization in a single location.

Description

Checklist

• [ ] New tests and/or benchmarks are included
• [ ] Documentation is changed or added

Motivation and Context

• [ ] Bugfix
• [ ] New feature
• [ ] Dependency update
• [x] Misc

Open Questions

Dependents

Types of changes

• [ ] Backport Needed
• [ ] Patch (non-breaking change which fixes an issue)
• [ ] Minor (non-breaking change which adds functionality)
• [ ] Major (fix or feature that would cause existing functionality to change)