add support to add files which describe "development" environments

[behrica]

Like

"Dockerfile" "devcontainer.json" "gitpod"

See a discussion here: https://clojurians.slack.com/archives/C03KCV7TM6F/p1676658872762339

It would probably be possible to come up with a "minimal" file for each them, which supports Clojure out of the box and could then be user extended.

So some form of a neil add .... command which would then generate this files on disk in a minimal (valid) form, which supports Clojure in the "environment".

[behrica]

I made once an attempt via a clojure library template to add them:

https://github.com/behrica/clj-py-r-template/tree/master/src/clj/new/clj_py_r_template

[behrica]

Can be done easily outside Neil