Adds AWS cloud shell instructions

[lsmithpanw]

Description

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• [ ] I have updated the documentation accordingly.
• [ ] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes if appropriate.
• [ ] All new and existing tests passed.

[welcome-to-palo-alto-networks[bot]]

:tada: Thanks for opening this pull request! We really appreciate contributors like you! :raised_hands:

[tkishel]

LGTM!

[welcome-to-palo-alto-networks[bot]]

:tada: Congrats on getting your first pull request merged! We here at Palo Alto Networks are so grateful! :heart: