Fix: Update module references to use terraform-random-tfe-utility external modules

Updated module sources to reference the external terraform-random-tfe-utility
repository with the pravi-postgres-passwordless branch that contains the
critical TFE environment variable fixes.

Changes:
- runtime_container_engine_config: ./modules -> git::...//modules/runtime_container_engine_config?ref=pravi-postgres-passwordless
- tfe_init: ./modules -> git::...//modules/tfe_init?ref=pravi-postgres-passwordless
- settings: ./modules -> git::...//modules/settings?ref=pravi-postgres-passwordless
- tfe_init_replicated: ./modules -> git::...//modules/tfe_init_replicated?ref=pravi-postgres-passwordless

These modules were referencing non-existent local modules and needed to
use the external modules that contain the proper environment variable
configuration for AWS RDS IAM authentication.

Author: raviharshicorp

main.tf

@@ -254,7 +254,7 @@ module "aurora_database" {
 # Docker Compose File Config for TFE on instance(s) using Flexible Deployment Options
 # ------------------------------------------------------------------------------------
 module "runtime_container_engine_config" {
-  source = "./modules/runtime_container_engine_config"
+  source = "git::https://github.com/hashicorp/terraform-random-tfe-utility//modules/runtime_container_engine_config?ref=pravi-postgres-passwordless"
   count  = var.is_replicated_deployment ? 0 : 1
 
   tfe_license = var.hc_license
@@ -346,7 +346,7 @@ module "runtime_container_engine_config" {
 # AWS cloud init used to install and configure TFE on instance(s) using Flexible Deployment Options
 # --------------------------------------------------------------------------------------------------
 module "tfe_init_fdo" {
-  source = "./modules/tfe_init"
+  source = "git::https://github.com/hashicorp/terraform-random-tfe-utility//modules/tfe_init?ref=pravi-postgres-passwordless"
   count  = var.is_replicated_deployment ? 0 : 1
 
   cloud             = "aws"
@@ -391,7 +391,7 @@ module "tfe_init_fdo" {
 # TFE and Replicated settings to pass to the tfe_init_replicated module for replicated deployment
 # --------------------------------------------------------------------------------------------
 module "settings" {
-  source = "./modules/settings"
+  source = "git::https://github.com/hashicorp/terraform-random-tfe-utility//modules/settings?ref=pravi-postgres-passwordless"
   count  = var.is_replicated_deployment ? 1 : 0
 
   # TFE Base Configuration
@@ -453,7 +453,7 @@ module "settings" {
 # AWS user data / cloud init used to install and configure TFE on instance(s)
 # -----------------------------------------------------------------------------
 module "tfe_init_replicated" {
-  source = "./modules/tfe_init_replicated"
+  source = "git::https://github.com/hashicorp/terraform-random-tfe-utility//modules/tfe_init_replicated?ref=pravi-postgres-passwordless"
   count  = var.is_replicated_deployment ? 1 : 0
 
   # TFE & Replicated Configuration data