Switches for Install & Run matches Consul & Vault

[markchristopherwest]

Could we please make the install switches the same for Nomad as they are in Consul & Vault i.e.:

terraform-aws-nomad/.../install-nomad

Nomad install does not have the same install switches (download & update option) as Consul & Vault do here:

terraform-aws-consul/.../install-consul
terraform-aws-vault/.../install-vault

All 3 allow for username, path & version however only Consul & Vault in terraform-aws-etc allow for URL & update skip i.e.:

  echo -e "  --download-url\t\tUrl to exact Vault package to be installed. Optional if version is provided."
  echo -e "  --skip-package-update\t\tSkip yum/apt updates. Optional. Only recommended if you already ran yum update or apt-get update yourself. Default: $DEFAULT_SKIP_PACKAGE_UPDATE."

Having the install experience be the same for each product improves the user experience. Although the current version does download from releases, it also forces package update. After all, is this not a great opportunity to create a Universal Install script which other teams might be able to leverage for emerging products?