Horizon should be more informative about floating IP lists

1. For now Horizon is unable to show floating IPs associated with a certain tenant. In Admin tenant (or for admin user) a tab/field/page should be added with the following info:
1) name and ID of the tenant,
2) floating IP associated for this tenant,
3) if this floating IP is associated with some instance or a router.

For example:
Tenant ID 1:
   floating IP 1 - router? instance?
   floating IP 2 - router? instance?
Tenant ID 2:
...

2. There should be possibility to disassociate floating IPs from a certain tenant (all or just checked ones).