Add service command

This change creates the `floaty service` command with two valid
arguemnts: types and examples

- `floaty service types` prints out a list of valid types for use in a
  service definition in ~/.vmfloaty.yml
- `floaty service examples` prints out example configuration files for
  both a single service and multiple services.

spec/vmfloaty/utils_spec.rb

@@ -77,9 +77,17 @@ describe Utils do
       expect(Utils.get_service_object).to be Pooler
     end
 
+    it 'uses abs when told explicitly' do
+      expect(Utils.get_service_object('abs')).to be ABS
+    end
+
     it 'uses nspooler when told explicitly' do
       expect(Utils.get_service_object('nspooler')).to be NonstandardPooler
     end
+
+    it 'uses vmpooler when told explicitly' do
+      expect(Utils.get_service_object('vmpooler')).to be Pooler
+    end
   end
 
   describe '#get_service_config' do