Document the Min Spec requirements are for the Toolkit

**Is your feature request related to a problem? Please describe.**

The Toolkit should have living documentation that communicates its minimum version requirements.
For example:
* VS Code version
* SAM CLI version
* etc

This likely takes the form of a version matrix for versions of the Toolkit.

Start by locating the Toolkit documentation and its release or version references. Inventory the minimum VS Code and SAM CLI versions for each relevant Toolkit version, then document them in a maintained version matrix.

Written by the indexing model from the issue text.