Add ability to pass runtime arguments

[jellers232]

Having the ability to pass runtime arguments would make hogan more flexible and reduce the number of templates needed if you have lots of modules that fall under an environment. A comma-delimited list or some other sort of way to pass in values.

script example

apps = ( admin api portal )
for a in "${apps[@]}"
do
  hogan transform -f 'example.template.json' -c hogan-configs/ -t ./product/ -args application="${a}"
done

hogan template file

variables {
  "application_name": "{{product}}-{{args.application}}"
}