Preparing for NGINX+Passenger server.

Added NGINX and Passenger installation and configuration files.
Migrated key generation to init script.

We now generate Puppet Master keys on startup before anything else runs
in an init script in `/etc/my_init.d/`.
Successfully served over Passenger+NGINX.

The Puppet Master is now correctly working as served over NGINX and
Passenger. We dealt with header issues which were giving us 403s. Need a
better way of regenerating the Puppet config file which doesn't
overwrite every single time.
Reworked generation of Puppet config to be failsafe.

Now, we backup the default configuration on container build then copy
this over if it's not present on container start. We also create the
right directories, chown everything, and template generate the
puppet.conf file as before.