WIP: Initial Jenkins EC2 Slave Bootstrap Script

This encapsulates the scripts that are manually applied inside the
Jenkins web UI into a single script. Initially, this is a direct port of
whats there. Longer-term this script will get a series of options and
settings that make it more robust and stable.

Change-Id: I91228c0c409693b4c769b1889c9ee84f413592f0