Add Block as a default permission

There are currently three permissions for specific sites: Block, Allow, Ask
However, only allow and ask (Ask before accessing can be either enabled or disabled) can be set as the default across all sites.

Please consider adding Block to default permissions.

This would permit a global default of Block for a permission across all sites rather than having to block each site individually. This would stop notifications and prevent having to block a permission for every (new) site visited. This would also add functionality currently present in Chrome.

(If this is already possible {which I was not able to find}, please forgive the waste of bandwidth!)