Minor documentation fixes and clean up formatting of JSON & CLI examples

[jveldboom]

Issue #, if available:

Description of changes: Documentation Fixes:

• Add s3:PutObject permission to this example policy which is required for code signing to save file to S3.
• Fix platform parameter on Amazon FreeRTOS OTA create-ota-update - here

Formatting changes:

• Clean up JSON formatting - like line indentions and line breaks
• Update long CLI examples to multiple lines for readability

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