Add SM-BC support to Trident

[mgrzybek]

Describe the solution you'd like

Trident should support the replication mechanism provided by SM-BC when using iSCSI protocols:

• managing two SVM
• managing the extended multipath provided by the "passive" SVM

Describe alternatives you've considered

We tried ONTAP Metro Cluster but the failover mechanism looks old fashion compared to SM-BC. This is a simple IP-based failover mode that does not use the multipath features of iSCSI. Moreover, SM-BC has a fine-grained scope that allows us to replicate some volumes groups instead of the whole storage hardware.

Additional context

N.A.