Add Documentation for the Usage of the Typescript Generator

[sarangan12]

We need the documentation for the Usage of the Typescript Generator and it should cover the following scenarios:

1. Creating SDK for a new Service
2. Migrating SDK to latest code generator from V4 Generator
3. Migrating SDK to latest code generator from latest code generator + core-http combination
4. Releasing new version of the existing packages, generated with the latest code generator