More permissive policies

1.1.0

Enable more permissive (read-only) IAM permissions for ECS Task exec …

Get SSM params-by-path, replace CD mod, add SG, update IAM

Add SSM get-by-path support, update IAM, CD mods, add SG (#1)

1) the container definition internal (sub-)module has been replaced with `cloudposse/ecs-container-definition/aws` - additional input vars have been added.
2) an `external` data source/provider is being used with a script to fetch all SSM parameters matching a path and pass them via a `null_resource` as secrets to the container definition
3) The Task Execution Role is now used by both EC2 and Fargate `launch_type`. The execution role incl. ECR permissions
4) Non-secret(SSM-based) environment variables can be passed as a list of maps to `container_envvars`
5) ECS service tasks have their own security group which allows all VPC traffic ingress, and egress to `0.0.0.0/0`, `concat` with a list provided as `awsvpc_security_group_ids`
6) Adds a `aws_vpc` data source based on the name provided as a (mandatory) input