Extension:CentralNotice/cn known mobile carriers table

Fields
Stores details on all the campaigns known to CentralNotice. Since v2.3

mc_id
Primary key. Identifying key for the campaign.

Schema summary
mysql> describe cn_known_mobile_carriers; +--++--+-+-++ +--++--+-+-++ +--++--+-+-++
 * Field           | Type           | Null | Key | Default | Extra          |
 * mc_id           | int(11)        | NO   | PRI | NULL    | auto_increment |
 * mc_name         | varbinary(255) | NO   | MUL | NULL    |                |
 * mc_display_label | varbinary(255) | NO  |     | NULL    |                |