User Story: As a network administrator managing multi-subnet IPsec policies, I want Nmstate to support configuration of multiple subnets for a single IPsec policy using leftsubnets and rightsubnets, ensuring that traffic to and from multiple subnets can be secured via a single IPsec tunnel. Acceptance criteria: Given a network administrator requires a setup where multiple subnets need to communicate securely through a single IPsec tunnel,  When they configure the IPsec policy using the leftsubnets and rightsubnets, specifying multiple subnets in the format { networkA/netmaskA, networkB/netmaskB, ... } , Then, Nmstate should process and apply the configuration, establishing IPsec tunnels that handle all specified combinations of subnet pairings as defined in the leftsubnets and rightsubnets. Definition of Done : The implementation meets the acceptance criteria Integration tests are written and pass The feature is part of a downstream build attached to an errata The release note text is filled and the official Nmstate documentation is updated The feature is backported into RHEL-9.4