v4.0

* save titlepage and coverpage to tex files so user has those.
* allow coverpage to be like titlepage
* allow user to use .yml for spec that way can have
```
include-files:
 - titlepage1.yml
 - titlepage2.yml
 - copyright.tex
 - dedic.tex
```

See this part about breaking up the metadata

https://quarto.org/docs/projects/quarto-projects.html

