Add mapped_drive define type

Hi all (@ppouliot, @virmitio,... ),

I've done the refactor of the types responsible of mapping drives to shared folders. Now, it's only one file that allows you to define the drives in the following way:

```puppet
 windows_common::client::mapped_drive { 'Z:':
   ensure       => present,
   server       => 'public.host.com',
   share        => 'folder',
 }

 windows_common::client::mapped_drive { 'Z:':
   ensure => absent,
 }
```

The old version is removed as it's easy to change to this new format. If you're using it and want to keep it for a while, we can include it again.

It includes as bonus an small readme and simple test case.
Please, take a look and let me know if it's ok to merge.