As a migration admin I want to configuring target VM scheduling preferences with fine-grained control over VM placement in the destination cluster.

Motivation
Currently, Forklift migration plans create VMs in the target cluster without providing operators control over VM scheduling and placement. This limitation prevents operators from:

• Ensuring VMs are placed on appropriate nodes based on workload requirements
• Implementing organizational labeling standards for migrated VMs
• Enforcing affinity/anti-affinity rules for performance or high availability
• Utilizing cluster resources optimally based on node capabilities

Proposed Solution
Introduce three new optional fields to the `PlanSpec`:

 TargetLabels

• {}Purpose{}: Apply custom labels to all VMs created by the migration plan
• {}Use Case{}: Organizational labeling, cost tracking, operational management

TargetNodeSelector

• {}Purpose{}: Constrain VM scheduling to nodes with specific labels
• {}Use Case{}: Ensure VMs run on nodes with required capabilities (GPU, storage type, CPU architecture)

TargetAffinity

• {}Purpose{}: Define hard and soft affinity/anti-affinity rules
• {}Use Case{}: High availability (spread across zones), performance optimization (co-locate related workloads)