Allow Custom Definition YAML

[austinsonger]

Is your feature request related to a problem? Please describe.
Custom Definition YAML

Additional context

It's difficult to use this for FedRAMP when I need to show all other non-aws services.

[a2ush]

Thank you for creating the issue!

Currently, we provide the method that you can use custom definition files as the following;
https://github.com/awslabs/diagram-as-code/blob/main/doc/introduction.md#definitionfiles-section

If you want to customize the resource definitions locally, you can specify a local file path instead:

    DefinitionFiles:
      - Type: LocalFile
        LocalFile: "<your definition file path (e.g. ~/Desktop/your-custom-definition.yaml)>"

Could you please confirm if this is the way to achieve your requirement?