Rename exercises dir

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

topics/aws/exercises/new_vpc/exercise.md

@@ -0,0 +1,6 @@
+## AWS VPC - My First VPC
+
+### Objectives
+
+1. Create a new VPC
+  1. It should have a CIDR that supports using at least 60,000 hosts

topics/aws/exercises/new_vpc/solution.md

@@ -0,0 +1,17 @@
+## AWS VPC - My First VPC
+
+### Objectives
+
+1. Create a new VPC
+  1. It should have a CIDR that supports using at least 60,000 hosts
+
+### Solution
+
+#### Console
+
+1. Under "Virtual Private Cloud" click on "Your VPCs"
+2. Click on "Create VPC"
+3. Insert a name (e.g. someVPC)
+4. Insert IPv4 CIDR block: 10.0.0.0/16
+5. Keep "Tenancy" at Default
+6. Click on "Create VPC"