Feature request : Optional Argument for custom services and custom regions scope for collect command

I have been faced with writing custom scripts for collection of various resources across services in AWS such as finding route53 domains and zones, or security groups across ec2 services.

Cloudmapper already has `collect` command which is used to collect resources. Having customised `collect` would really help people who want only a specific collection to be done rather than collection of all resources.

The expected command would look something of this kind :-
```
python3 cloudmapper.py collect --regions us-east-1 us-west1 --services iam route53 ec2 --account my_aws_account
```
This request also stems from one of the asks from the Cloud Security Channel where the person wanted route53 zones and recordsets to be dumped.

This would be helpful for people who may want to use cloudmapper for it's collection capability. This may impact the existing audit modules which is dependant on the collections , but some collection metadata json can be created, reading which the modules can come to know about the coverage of collection based on which it can give appropriate warning or error to the user mentioning required collection data does not exist for audit to proceed or something of that nature.