enhancement: provider level tags

[pvlbnkl]

Add provider level tags to examples according to whitepaper here: https://docs.aws.amazon.com/whitepapers/latest/tagging-best-practices/tagging-best-practices.html

Also ran terraform fmt

Issue: #232

[wallhided]

I'll test it out.

[wallhided]

I've checked terraform code on branch.
A list of things to cover in that PR:

1. Terraform code is not valid, the declaration of default_tags, the proper blocks declaration could be found here.
2. The idea of having this block - is to stop adding same tags for each terraform resource. For instance, there are some duplicates of these tags (see provider.tf and "vpc" module in example/argocd). Please remove setting of same tags from terraform resources.
3. Comments in code.

[wallhided]

"Environment" and "Project" values could be retrieved from variables.

[wallhided]

Still not fixed

[wallhided]

It is incorrect declaration of default_tags for my terraform version. Does it work for your terraform version?

[wallhided]

Good job, the main problem is fixed. One small change is required - some tags could be retrieved from terraform vars.