Terraform Onboarding: employ versioning for customer template/module/provider

[sdorr0]

Currently, the cloud onboarding terraform option doesn't employ any form of versioning (like the transfluo terraform deployments use). This means it's possible for us to implement terraform changes that would break existing customers' terraform setups.

Let's add versioning to each of the three layers (customer provided .tf, kentik hosted module, kentik authored provider) so that breaking/significant terraform changes would generate a new version, end to end, letting existing customers' deployments continue to work as expected.