V5 Add Lighten Buttons

Created by: devhoussam

It will be similar like this example :

<button type="button" class="btn btn-lighten-primary">Lighten Primary</button>
<button type="button" class="btn btn-lighten-secondary">Lighten Secondary</button>
<button type="button" class="btn btn-lighten-success">Lighten Success</button>
<button type="button" class="btn btn-lighten-danger">Lighten Danger</button>
<button type="button" class="btn btn-lighten-warning">Lighten Warning</button>
<button type="button" class="btn btn-lighten-info">Lighten Info</button>