Testnet token access guide

[bradleycamacho]

Description

Create a complete SDK documentation

Action items

1. Do research on topic and raise any questions with the docs team
2. Write a first draft. It doesn't have to be worded perfectly as the docs team will review
3. Ping @bradleycamacho on discord and request review
4. Implement feedback from @bradleycamacho
5. Publish