chore: move to export pg connection string

provider.tf

@@ -11,9 +11,7 @@ terraform {
     }
   }
 
-  backend "pg" {
-    conn_str = var.PG_CONN_STR
-  }
+  backend "pg" {}
   encryption {
     key_provider "pbkdf2" "mykey" {
       passphrase    = var.passphrase
@@ -66,11 +64,6 @@ variable "passphrase" {
   sensitive = true
 }
 
-variable "PG_CONN_STR" {
-  type      = string
-  sensitive = true
-}
-
 provider "proxmox" {
   pm_api_url  = var.proxmox_api_url
   pm_user     = "root@pam"