Add two more agents than there are cores.

Several steps in the build process are not processor bound, but
IO-bound.

  - Downloading artifacts from Nexus or Bower repositories.
  - Uploading built artifacts to package repositories.
  - checking out code from SCM
  - notifiying Ansible Tower
Add agent dependencies

This commit adds dependencies for git, github (with no outbound ssh),
maven, memcache, and nexus.

You will need to provide the following env vars:

```sh
GITHUB_USER=
GITHUB_USER_EMAIL=
GITHUB_ACCESS_KEY=
NEXUS_USER=
NEXUS_PASSWORD=
NEXUS_URL_ROOT=
```
Comment out ufw and firewalld because they fail --check mode
Add variable for Go user home
Add task to fetch everydollar-ops-go-shell-scripts
Java-based build working

Add maven, AWS CLI, build scripts from GitHub, symlink bna gem
Adds tower-cli

also adds notes from review
Adds node

additionally,
  - removes extra maven file
  - moves gocd user home to /opt
  - adds two more build agents
Do not enable http on port 8153 in iptables
Add SASS gem