Merge branch 'docs-aws-rds-instance-type' into 'master'

Add warning against burstable db instances

See merge request gitlab-org/gitlab!31574

doc/install/aws/index.md

@@ -297,6 +297,8 @@ We need a security group for our database that will allow inbound traffic from t
 
 ### Create the database
 
+DANGER: **Danger:** Avoid using burstable instances (t class instances) for the database as this could lead to performance issues due to CPU credits running out during sustained periods of high load.
+
 Now, it's time to create the database:
 
 1. Navigate to the RDS dashboard, select **Databases** from the left menu, and click **Create database**.