Updates from bitrot livestream (#16)

- Remove minor version pin for postgres versions (i.e. 12.5 -> 12)
- Update s3 config to use separate versioning and encryption terraform resources
- Use bucket_prefix instead of bucket for bucket naming to avoid name conflicts

Stream: https://youtu.be/KWwKPYuOGBw

06-organization-and-modules/web-app-module/variables.tf

@@ -34,8 +34,8 @@ variable "instance_type" {
 
 # S3 Variables
 
-variable "bucket_name" {
-  description = "name of s3 bucket for app data"
+variable "bucket_prefix" {
+  description = "prefix of s3 bucket for app data"
   type        = string
 }