This PR adds a Dockerfile that sets up miniconda and pyodide inside a docker image, along with epython installed from source.

This will mitigate current environment issues that we are having with pyodide. Eventually, the goal here will be to run epython, generate a simple .wasm script, and then hook into pyodide as a package that can be imported and used.

Currently, the dockerfile is dirty and could use additional help (i.e. docker stack using docker-compose), but this works for our current use-case.

cc: @cleonard @verhulstm