A few years back, there were efforts to support the creation of pip-installable user packages by preparing project templates that provide some common infrastructure for building and testing etc.
Both templates appear to have fallen out of maintenance (in particular they do not reflect the current practices in Python packaging). More recently we have taken to recommending that people should just imitate what well-maintained existing projects are doing.
One of the weaknesses of using templating mechanisms: Creating a project once is fine, but updating it afterwards is manual work.
It is compatible with the popular "cookiecutter" package and appears to work well.
I would suggest a new community effort to develop these templates, to update existing project and to stimulate the development of a package ecosystem downstream of the Sage library.