fix: added ports to endpoints in README
Services can have multiple URIs

rewrote Service class to use a many-to-many association for
URIs and service prefixes

adjusted squidwork.quick pub and sub functions to accept
varargs ZeroMQ uris

added python -m squidwork.config -c SOME_CONFIG, which will print
out all the Services in that config file

updated config package, tests, and example config file to reflect
the new APIs