Add ability to use inputs with dollar signs in them

[jbeemster]

Currently if you have an input variable to the module that has a $ and this variable gets passed into a terraform template file it can end up being dynamically redacted to an empty string.

For example if the db_password starts with a $ the config that lands on the scale-set will have the password read as "".

---

One strategy to prevent this issue would be to base64 encode the config in Terraform, pass it to the user-data script, then base64 decode it there to avoid the inference.