Add documentation for MongoFlow (#6)

* Add solution items and update README

Included new items to the solution such as global.json, icon.png, README.md, and LICENSE.md. Enhanced README with comprehensive setup and usage instructions for MongoFlow including configuration, document operations, query filters, interceptors, and transaction management.

* Expand interceptor documentation in README.md

Updated the interceptors section to clarify that MongoFlow interceptors can operate both before and after database operations. This provides a more complete understanding of the feature's capabilities.

* Refactor README.md for clarity and conciseness

Reformatted features section with icons for better readability. Reorganized configuration and usage examples for improved structure and clarity. Enhanced code snippets to highlight key functionalities and improve understanding.