Add AWS account id to config recorders and cloudwatch metrics

[gsoltis]

• Include the path in the context for uri functions. This allows use of things like org and account ids
• Include account id in made-up URIs. Some resources don't have published arns, and may conflict between accounts in the same organization (and hence same provider_account_id) if the URIs don't also include the account id.
  • config recorder
  • cloudwatch metric

Fixes #18