Hyp3 Deployment ReadMe Edits

[ZachHoppinen]

Adding in ReadMe clarifications and edits from my first hyp3 deployment.

Changes include:

• Added in overall motivation for setting up a hyp3 deployment
• clarify access key creation (I ended up doing this twice to rename and know where I would need to use it again)
• Clarify Warning about deploying ASF CI/CD stack
• Clarify formatting of editing asf.alaska.edu.db for SSL cert
• add example formats for all items in environment
• Clarify naming of github environment
• Add tip on deleting rolled back stack before re-running failed job
• clarify adding DNS record for API
• Add section on "Testing and adding user credits"
• Other small changes to make the flow actually match what you see on AWS