Prevent version mismatch with Reticulum

[bryanenders]

This PR has a Release Strategy

Why

The Elixir and Erlang versions are specified in both repositories, this one and Reticulum. If a developer pulls a commit that contains a tool version change in one of the repos, a version mismatch occurs.

What

• Move dockerfile from Hubs Compose into Reticulum
• Move container files into Reticulum
• Remove perfunctory dev targets
• Move commands and entrypoints into dockerfiles

Release Strategy

Deploy https://github.com/mozilla/reticulum/pull/681 before merging this PR.