Consolidate testdata and delete unused output files

[codesue]

What does this pull request do?

• Moves test data in template/test to utils/testdata
• Deletes unused rendered model card outputs, which also don't seem to be updated when templates are updated

How did you test this change?

Applied changes in #254 and ran pytest model_card_toolkit.

How did you document this change?

N/A

Before submitting

Before submitting a pull request, please be sure to do the following:

• Read the How to Contribute guide if this is your first contribution.
• Open an issue or discussion topic to discuss this change.
• Write new tests if applicable.
• Update documentation if applicable.

[codesue]

Hi @casassg, @deutranium, or @hanneshapke, would you please review this when you get a chance. 🙏

[deutranium]

Lgtm! Thank you for contributing!!