doc changes and remove computed true for database_name

Author: Uddipaan Hazarika

docs/resources/database_postgresql.md

@@ -67,7 +67,7 @@ resource "delphix_database_postgresql" "source" {
     * `key` - Key of the tag
     * `value` - Value of the tag
 
-## Import (Beta)
+## Import
 
 Use the [`import` block](https://developer.hashicorp.com/terraform/language/import) to add source configs created directly in Data Control Tower into a Terraform state file. 
 
@@ -79,5 +79,3 @@ import {
 }
 ```
 
-*This is a beta feature. Delphix offers no guarantees of support or compatibility.*
-