DEV-2768: Standardize Builder & Document Props & Add Type Hints.

[BenX00]

Changes to the builder:

• This moves all class level properties to be either module level constants or instance level fields.
• Adds doc strings for all constants, constructor args/instance fields, and instance level cache fields.
• Type hints all methods in the Builder.
• Removes dead code.
• Removes test logic from production code.