AWS::Cloudformation::Macro without needing a stack

## Scope of request
`AWS::Cloudformation::Macro`'s can only be uploaded by using a stack. Other services like lambda allow you to create resources without needing a stack. Macros are typically used across stacks so it just feels like a strange requirement.

## Expected behavior
Ability to create aws macros via aws-cli without needing a template.yaml file

The request concerns AWS::CloudFormation::Macro creation through the aws-cli without a template.yaml file. Start by reviewing the current CloudFormation macro and CLI entry points and their documentation. Done would mean an approved stack-independent creation path, but the issue names no repository files or tests.

Written by the indexing model from the issue text.