Missing documentation for the pdk.yaml file

[hbrown-uiowa]

Describe the bug
There appears to be no documentation of the pdk.yaml file to be found. It would be nice to have a page that documents the file's purpose as well as descriptions of which config items can go in there and what those config items do.

To Reproduce
Search for documentation on pdk.yaml and notice that the closest you can get is pdk get config from the pdk documentation.
Search for information on project.validate.ignore or user.pdk_feature_flags or user.pdk_feature_flags.available and come up empty.

Expected behavior
A link off the PDK documentation that details the config items possible in pdk.yaml. The info for .sync.yml on https://www.puppet.com/docs/pdk/3.x/customizing_module_config.html#customizing-the-default-template is similar to what I'd hope for with pdk.yaml.

Additional context

• Your PDK installation method: native package
• Your PDK version: 3.3.0
• Your operating system / platform: Linux Fedora 40