Tell users how to get started with the SDK.

[johnnymatthews]

Child of #287

Create a Getting started guide that covers how to install the SDK, configure it, and some basic uses.

Proposed solution

Create a page at /reference/sdk/get-started with the following sections:

• Installation steps
• Basic configuration
• First-time dev walkthrough
  • Define basic use case
  • Set up a test
  • Run the SDK against that test
  • Get an expected output
• Troubleshooting steps and/or common errors that users may run into.

Checklist

I confirm that I have:

• Checked to see if there are any existing issue that cover this topic.
• Linked to any relevant issues across all entropyxyz repos.