Start an nREPL using JVM Opts (Like socket REPL)

It's not possible to start the clj tools in jack-in with a main or additional -e options.

Starting the nREPL should be similar to starting a socket REPL. If it was a JVM opt it can be placed as the first parameter, always, as CLJ doesn't distinguish on order.

Using JVM opts in this way would also benefit production systems which wish to add nREPL. Currently it requires being able to evaluate code early, or altering the component/integrant/mount system in order to load nREPL in production (but not in dev, because leiningen does that!). This would also open up nREPL for easier use with general java software systems, such as Datomic.

Start by tracing how jack-in handles main and additional -e options, then compare that path with socket REPL startup. Determine how JVM options could be accepted first without depending on evaluation order, and verify that the resulting nREPL startup works for production and general Java systems as described.