Rename exercises dir

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

topics/aws/exercises/snapshots/exercise.md

@@ -0,0 +1,16 @@
+## AWS EC2 - EBS Snapshots
+
+### Requirements
+
+EBS Volume
+
+### Objectives
+
+A. Create a snapshot of an EBS volume
+B. Verify the snapshot was created
+C. Move the data to another region
+D. Create a volume out of it in a different AZ
+
+## Solution
+
+Click [here to view to solution](solution.md)