Add Erlang module

Based on work by bhuztez@gmail.com - https://github.com/bhuztez/osv-erlang
with the following minor changes:

 1. Add module.py and usr.manifest to allow building and running OSv with
    Erlang without Capstan: "make image=errlang; scripts/run.py"

 2. Fix Makefile's dependencies to make parallel make work correctly.

This module doesn't currently running because of a missing getaffinity()
and sysconf(_SC_OPEN_MAX) implementations.

It also disables a lot of Erlang features during build (see Makefile) which
should be gradually returned.

Signed-off-by: Nadav Har'El <nyh@cloudius-systems.com>
httpserver plugin examples