Chore: Misc updates

[ryan-roemer]

• Update to Node 12.13.0 runtime
• Update to Terraform 0.12.10 via tfenv (since we're using instructions from aws-lambda-serverless-reference which now uses tfenv)
• Update all package.json dependencies
• Minor bugfixes
• Make yarn cf:bootstrap:_delete empty buck objects.
• Add tags everywhere (TF and SLS)
• Add a resource group.
• Update terraform-aws-serverless module dependency.
• Use serverless-jetpack for SLS packaging.