Correctly error when missing required files from bundle

[dotNomad]

Currently we do not have helpful errors aside from when the Config.Python.PackageFile file is missing from the included files list, and that one contains a bug: #2563.

A improvement can be made here. One potential option is to insert the checks in between the create and upload bundle operations in internal/publish/bundle.go.

We can utilize the files list inside of the manifest and the Config inside of the defaultPublisher state to check if the package files, and the entrypoint are included with a helpful error.

Related Issues

• Don't allow requirements.txt and renv.lock files to be excluded from projects #1503
• Don't allow entrypoint file to be excluded from Project #1493
• "Missing dependency file requirements.txt" error when using wildcard inclusion #2563 (see sub-issues list)