Add Erlang Jenkins Slave and Erlang S2I image

[InfoSec812]

Overview

Add the ability for Jenkins to run a slave which can build Erlang applications using Rebar3. Also, add an S2I image build which can convert an Erlang release to a runnable container image using Rebar3

Acceptance criteria

• A new Jenkins slave image which has Rebar 3 and Erlang/OTP installed for use with creating a "release"
• A new S2I image which can take an Erlang release created via Rebar 3 and create a runnable container
• A new example Erlang project which can be run through the CI/CD pipelines to produce an runnable application
• Update tests to show that the Erlang pipeline is functional

[springdo]

@InfoSec812 I think the plan is to migrate all the Jenkins slaves we have to the CoP https://github.com/redhat-cop/containers-quickstarts . Perhaps raise this there?

[InfoSec812]

Closing in favor of https://github.com/redhat-cop/containers-quickstarts/issues/101