This worklog introduces dynamic global privileges and split
the global SUPER privilege ID into a set of more fine grained
privilege IDs.
* New Privilege IDs introduced:
 - FIREWALL_ADMIN
 - FIREWALL_USER
 - AUDIT_ADMIN
 - SYSTEM_VARIABLES_ADMIN
 - ENCRYPTION_KEY_ADMIN
 - BINLOG_ADMIN
 - VERSION_TOKEN_ADMIN
 - ROLE_ADMIN
 - REPLICATION_SLAVE_ADMIN
 - CONNECTION_ADMIN
 - GROUP_REPLICATION_ADMIN
 - SET_USER_ID
* New system table: mysql.global_grants