refactor: update code convention for file naming and change code to the desired state

[mglotov]

Prerequisites

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• I am running the latest version
• I checked the documentation and found no answer
• I checked to make sure that this issue has not already been filed

Expected Behavior

It's needed to choose 1 solution or several and update doc to make naming process as clear as possible
Possible solutions for layer1-aws:

1. Group resources by type in layer1-aws (for example: all s3 buckets are described in aws-s3.tf, all security-groups in aws-sg.tf, etc). In this way it's very easy to find and update resources of the same type. However
   PROS:
   * it's very easy to find and update resources of the same type
   CONS:
   * It's difficult to identify what resources are created for one function (we created aws-eks-auth.tf, aws-kms.tf, aws-eks.tf files to provision EKS cluster)
   * If we have lots of buckets, it will be very difficult to find the necessary one without using search
2. Use suffixes to identify type and function (for example: aws-s3-cloudtrail.tf, aws-sns-eventbridge.tf, aws-kms-eks.tf, where the first part after AWS is type of services and the second part is function or for what this s3 bucket or SNS topic are used)
   PROS:
   * it's clearer than in previous option where resource is used and how it's connected with others.
   CONS:
   * the more resources we have, the more difficult it's to manage large number of files.
3. Use the same approach as we use for layer2-k8s, i.e. group resource by function/feature. For example, group all resources needed to provision EKS cluster in one file aws-eks.tf, group all resources needed to configure alerts based on CIS benchmark in one file aws-cis-benchmark-alerts.tf
   PROS:
   * the one approach is used for both layers
   * it's the easiest way to find all resources related to one function/feature
   CONS:
   * it sometimes can be unclear what resources are created without reading files (aws-cis-benchmark-alerts.tf)
   * it's difficult to update one type module version (module s3, module sg, etc)

Current Behavior

It isn't clear now what names to use for files in layer1-aws folder. There is a code convention with the next item https://github.com/maddevsio/aws-eks-base/blob/main/.github/CONTRIBUTING.md#names-of-terraform-files-directories-and-modules. However, it doesn't cover layer2-k8s, because we decided to use another approach to group resources there.
So, there are several ways how we group resources and name files (especially big difference between layer1-aws and layer2-k8s).

[mglotov]

Decided to use the third way, at least for this boilerplate + infra stuffs (not related to developed apps).