Filter AWS resources by tags

[meshuga]

It's a good practice on AWS to perform resource tagging (https://aws.amazon.com/answers/account-management/aws-tagging-strategies/) and many projects use a single AWS account which result in a high number of resources that are grouped by tags. Because of that, it's often useful to export resources based on tags, rather than ids (what is currently possible in Terraformer).

Because of that it would be a good to be able to export AWS resources based on tags.

It might be useful to have such functionality also in GCP/Azure although I'm not proficient in those cloud providers.