feat(network): add metrics for conntrack sync

[loktev-d]

Description

New conntrack sync metrics:

Metric	Labels	What it tells you
kubevirt_vmi_conntrack_sync_exports_total	result={success,skipped,error}	Whether CT was exported from Cilium and sent to the target
kubevirt_vmi_conntrack_sync_exported_bytes_total	—	Total bytes of CT data sent across all migrations
kubevirt_vmi_conntrack_sync_imports_total	result={success,aborted,error}	Whether CT import on the target node succeeded
kubevirt_vmi_conntrack_sync_hook_waits_total	result={completed,timeout}	Whether the virt-launcher hook got the injection confirmation in time

Why do we need it, and what problem does it solve?

What is the expected result?

Checklist

• The code is covered by unit tests.
• e2e tests passed.
• Documentation updated according to the changes.
• Changes were tested in the Kubernetes cluster manually.

Changelog entries

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[deckhouse-BOaTswain]

Workflow has started.
Follow the progress here: Workflow Run

The target step completed with status: failure.

[deckhouse-BOaTswain]

Workflow has started.
Follow the progress here: Workflow Run

The target step completed with status: failure.