Support ignoring files when creating projects with templates

[rudeigerc]

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

PDM template is a helpful feature, but sometimes we do not expect certain files to be included in the project to be created with the template, such as documentation of the template itself, or configurations bound with editors.

Describe the solution you'd like

It would be helpful to provide the ability to define ignored file patterns in a file like .pdm-template-ignore.

Related configuration in copier: https://copier.readthedocs.io/en/stable/configuring/#exclude

[pawamoy]

So, you would like PDM to support .pdm-template-ignore files in basic templates (non-Copier, non-Cookiecutter templates)?

[rudeigerc]

@pawamoy Affirmative.