Tweaks to Terraform + create script

[donaldgray]

Made the following changes to Terraform:

• Removed "-cloudwatch-cron-rule" postfix from CW event name, there's a 64 char limit and this adds 22 chars.
• Add description + types to variables.tf
• Ran terraform fmt and remove unused region variable
• Reduce the ssm permissions for the lambda by restricting to a specific SSM value.

In addition to the above this PR:

• Adds a sample sql script for creating different pg users for running scripts
• Removes 2 unused vars from entity-counter py script
• Explicitly sets the "CustomerStorage" column names as the ordering is inconsistent between different DLCS setups (due to some created with legacy sql script and EF).