refactor: set KB bucket prefix, not whole name

Configure Knowledge Base S3 bucket prefix, rather than full name, in
Terraform KB module, to avoid hard-coding global resources which make
it more complex to deploy copies of the stack across AWS accounts/etc

Author: athewsey

infra/modules/kb-stack/main.tf

@@ -1,6 +1,6 @@
 # S3 Bucket for Knowledge Base
 resource "aws_s3_bucket" "kb_bucket" {
-  bucket = var.bucket_name
+  bucket_prefix = var.name
 }
 
 resource "aws_s3_bucket_public_access_block" "kb_bucket_pab" {

infra/modules/kb-stack/variables.tf

@@ -3,11 +3,6 @@ variable "name" {
   type        = string
 }
 
-variable "bucket_name" {
-  description = "S3 bucket name for knowledge base data"
-  type        = string
-}
-
 variable "kb_model_arn" {
   description = "ARN of the embedding model for the knowledge base"
   type        = string

infra/variables.tf

@@ -16,10 +16,6 @@ variable "kb_stack_name" {
   type        = string
 }
 
-variable "kb_bucket_name" {
-  description = "S3 bucket name for knowledge base data"
-  type        = string
-}
 
 variable "kb_model_arn" {
   description = "ARN of the embedding model for the knowledge base"