Add Erlang support

Add Erlang support for cats-judge.
To install Erlang:
1. Check out Erlang binaries form http://www.erlang.org/download.html
(or https://www.erlang-solutions.com/downloads/download-erlang-otp)
2. Install binaries into directory, which is referred in config file.

Important: "-run init stop" parameter is needed to stop Erlang VM after
execution.