Integrating Documentation Revisions from Game Day

[forestmvey]

Summary

Integrate all changes noted in the feedback from game day.

Description

Add the following changes into the documentation for the Prometheus Connector:

• Note lack of support for the session_token field for MFA authenticated AWS users
• Note the format for the contents of the password file used for authenticating the AWS user in the Prometheus configuration
• Note the requirement for needing the absolute path of the password file in the Prometheus configuration
• Note that the deployment user policy is too long to be set inline during user creation
• Remove global section in the example for the Prometheus configuration file
• Add region portion to the CLI commands that create the timestream database and tables

Resolved Issues:

• N/A

[forestmvey]

As there are no code changes in this PR and only documentation revisions which have already gone through a round of reviews, I am merging.