Created S3 buckets should block public access

## Background

It is a best practice to block public access to S3 buckets. The module currently creates a number of S3 buckets publicly.

## Desired Change

Something akin to the below. Perhaps it should be enabled by default, where a variable is provided to disable it if need be.

```hcl
resource "aws_s3_bucket_public_access_block" "block_binaryalert_bucket" {
bucket = BUCKET_IDs
restrict_public_buckets = true
block_public_acls = true
block_public_policy = true
ignore_public_acls = true
}
```

Start by locating the Terraform module definitions for the S3 buckets created by BinaryAlert and review how their configuration variables are handled. Add default public-access blocking with the requested opt-out behavior, then validate that every created bucket is covered and run the available Terraform validation or tests.

Written by the indexing model from the issue text.