What would you like to be added:
I would love if the default template for the json output format was provided under the templates path: https://github.com/anchore/grype/tree/main/templates

Even better if all the other formats were provided there as examples too.

Why is this needed:
It makes it much easier to craft my own template as I can start from the json one and just remove the fields I don't want.

Additional context: