Add Dockerfiles to project templates as best-practice

Problem to solve

Herokuish is slow. We can dramatically speed up build times by including a Dockerfile. We should do this for our project templates as a best practice to encourage.

Further details

Node.js project template takes 3 minutes to build with default Auto DevOps.

Proposal

Add Dockerfiles based on alpine to each of the project templates.

What does success look like, and how can we measure that?

Faster demos and encouraging a better practice for users starting from the templates.

Links / references