docs: update cloudformation reference

[jmdeal]

Fixes #N/A

Description

This PR makes two sets of docs updates related to the new IAM policy structure:

• Updates the getting started guide script for fargate installations to use the new policy
  • The instructions for MNGs had been updated previously, Fargate was missed
• Updates the cloudformation reference page to document the new policies

How was this change tested?
make website

Does this change impact docs?

• Yes, PR includes docs updates
• Yes, issue opened: #
• No

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[github-actions]

Preview deployment ready!

Preview URL: https://pr-8958.d18coufmbnnaag.amplifyapp.com

Built from commit 1af7cc9b738591ce977d72382b0c85cfd8430689

[coveralls]

Pull Request Test Coverage Report for Build 21882225822

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 13 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.1%) to 67.483%

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Files with Coverage Reduction	New Missed Lines	%
pkg/fake/iamapi.go	5	57.69%
pkg/providers/instanceprofile/instanceprofile.go	8	81.22%

Totals
Change from base Build 21877387811:	-0.1%
Covered Lines:	7830
Relevant Lines:	11603

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💛 - Coveralls

[jigisha620]

LGTM 🚀