Use cookiecutter project name for backend specification

[d33bs]

This PR uses the cookiecutter project name for backend specification (Terraform throws an error when attempting to use tfvars).

Thanks for any feedback!

Closes #12

[falquaddoomi]

I wish I'd read this PR before the other one about variable slicing...I wonder if cookiecutter has a means for validating inputs, e.g. to make sure they're not exceeding GCP's limits. I imagine it'd be a lot easier for the person to fix the issue when running cookiecutter than way down the line when they're attempting to run Terraform.

If there isn't a way to do it in cookiecutter, perhaps you could populate tfvars via cookiecutter, then use TF's input validation (as I mentioned in the other PR) to check those variables? At least in that case the edits are all contained in the tfvars file rather than being spread across the TF code.

If all that sounds too complicated, that's fine; I think handling the errors as you were doing in the other PR works.

[d33bs]

Thanks @falquaddoomi ! I think your advice is spot on and incorporated it into #20 . I believe we still need the changes here due to TF limitations (we can't use a TFvar in the backend specification) but cookiecutter should catch things before we get to a point where the backend bucket name exceeds that of what's possible (through the project name checks in cookiecutter).

[d33bs]

Thanks again @falquaddoomi, merging this in after related changes passed testing.