Support for custom template paths, additional improvements

[reteps]

This PR adds:

• Output path templating for the markdown output files (Closes #728 )
• Output path templating for graphviz output files (Closes #728 )
• Support for an Enum template in markdown (Closes #729 )
• Support to skip file generation by setting the output path to the empty string (Closes #732 )
• Support for a shortName template field/attribute (Closes #730 )
• Hides the table description header if there is no comment or table definition (Closes #731 )

This code was written with the help of Claude 4.0

[k1LoW]

Thanks for the contribution!

I don't understand why this fix is needed, and there are many fixes in one. I cannot accept it at this time.

[reteps]

Hi @k1LoW -- if I split each change up into it's own PR, would that help each feature be accepted? These features are super useful for customizing the output of tbls for our project.

[reteps]

To provide some more context, I am trying to replace our in-house solution with tbls, and these are the minimum features to add to replace it. The path templating is useful because it gives us extra flexibility in creating directories/files in our preferred structure.

[reteps]

I'm happy to write up additional use cases or tests as wanted!

[reteps]

@k1LoW Let me know what you think 😄

[k1LoW]

It would be great to know in what cases each modification would be useful and why it is necessary (and why it needs to be incorporated as a feature in tbls).

It may be less costly to have the conversation in an Issue rather than splitting this Pull Request first.

[reteps]

@k1LoW I split those up into issues and linked them here 👍