v4.0.0b1 release

A complete, ground-up rewrite of the SDK.

Key changes:

• Monorepo structure, with each API under separate packages
• Targeting Python 3.9+
• Feature parity with v3
• Add support for the new network APIs - the Vonage Sim Swap Network API and the Vonage Number Verification Network API
• Usage of data models throughout
• Many new custom errors, improved error data models and error messages
• Docstrings for methods and data models across the whole SDK to increase quality-of-life developer experience and make in-IDE development easier
• Use of Pydantic to enforce correct typing throughout
• Add support for all Vonage Video API features
• Add http_client property to each module that has an HTTP Client, e.g. Voice, Sms, Verify
• Add last_request and last_response properties to the HTTP Client for easier debugging
• Migrated the Vonage JWT package into the monorepo
• With even more enhancements to come!