Enhancement: Support for secondary IP on floating SVI

[robvand]

The L3out module offers support floating SVIs. The interfaces ip_shared attribute is available to set a secondary IP. The ip_shared attribute is not used when configuring a floating SVI.

Example of floating svi secondary IP DN:
uni/tn-isovalent/out-isovalent.vrf-01-bgp-AS-65152/lnodep-border-leafs/lifp-hx-dev-01-fi-a-vlan-16/vlifp-[topology/pod-1/node-101]-[vlan-16]/addr-[1.1.1.1/24]

Example of svi secondary IP DN:
uni/tn-isovalent/out-isovalent.vrf-01-bgp-AS-65152/lnodep-border-leafs/lifp-hx-dev-01-fi-a-vlan-16/rspathL3OutAtt-[topology/pod-1/paths-101/pathep-[hx-dev-01-fi-a]]/addr-[1.1.1.1/24]

The module should allow user to configure shared_ip on floating SVI.