Add overly matching detection and MozDef alerting to AWS-Federated-AMR.js

[gene1wood]

We should extend the Auth0 rule which creates the amr claim to detect overly matching policy group names (e.g. e) which effectively permit a ton of people and undermine the benefits of the group filtering feature

https://github.com/mozilla-iam/auth0-deploy/blob/master/rules/AWS-Federated-AMR.js

When cases like this are detected we could

• Alert to MozDef that a overly matching policy was authored
• Ignore the overly matching group name when filtering
• Maybe have a whitelist of group names which both match our "is this overly matching" logic but also should indeed be allowed

Original Jira issue IAM-139