Adds VM Manager implementation for UVM (microsoft#2597)

Add vmmanager package for HCS-backed UVM lifecycle and configuration

Implements the foundational `UtilityVM` along with the full set of host-side resource interfaces (LifetimeManager, NetworkManager, SCSIManager, PCIManager, PipeManager, Plan9Manager, VMSocketManager, VPMemManager, VSMBManager, and ResourceManager).

Key aspects:
- Provides the `Create` and `Start` flows for UVMs using hcsschema.ComputeSystem.
- Tightly couples with the HCS backend for host-side executions.
- Enforces a stateless design, leaving state management to the orchestration layer above.

Signed-off-by: Harsh Rawat <harshrawat@microsoft.com>

Author: rawahars