Rename exercises dir

Name it instead "topics" so it won't be
strange if some topics included "exercises" directory.

topics/aws/exercises/alb_multiple_target_groups/exercise.md

@@ -0,0 +1,15 @@
+## AWS ELB - ALB Multiple Target Groups
+
+### Requirements                   
+
+Two EC2 instances with a simple web application that shows the web page with the string "Hey, it's a me, `<HOSTNAME>`!"
+One EC2 instance with a simple web application that shows the web page with the string "Hey, it's only a test..." under the endpoint /test
+
+### Objectives
+
+1. Create an application load balancer for the two instances you have, with the following properties
+  1. healthy threshold: 3
+  2. unhealthy threshold: 3
+  3. interval: 10 seconds
+2. Create another target group for the third instance
+  1. Traffic should be forwarded to this group based on the "/test" path