[DOCS] Need to document the process for downloading/installing nightly package builds

Description of Issue

Right now, the install guide only provides guidance for download/install of full releases.

• Directions for nightlies are missing

This issue is opened because we should document the process for installing nightly builds.

Guidance

# Install tools from inside of the salt repo
pip install -r .\requirements\static\ci\py3.10\tools.txt

# Set an env token
## Windows
$env:GITHUB_TOKEN="ghp_123abclongrandomtoken"
## Linux
export GITHUB_TOKEN="ghp_123abclongrandomtoken"

# Download the artifacts
## $run_id is the id of the test run. It's that first number in the completed nightly workflow url
## ex. 15101387617
## The $slug would be the OS you want
## ex. windows-2022 to get the Windows artifacts
tools ts download test-artifacts $run_id $slug

Version

N/A

Operating System

N/A

Relevant log output