feat(module): add annotations for kubevirt migration settings

[yaroslavborbat]

Description

Replaced the standalone parallel-outbound-migrations-per-node hook with a unified migration-config hook that manages all KubeVirt migration parameters via ModuleConfig annotations.

New configurable parameters (via ModuleConfig annotations):

• virtualization.deckhouse.io/bandwidth-per-migration (default: 640Mi)
• virtualization.deckhouse.io/completion-timeout-per-gib (default: 800)
• virtualization.deckhouse.io/parallel-outbound-migrations-per-node (default: 1)
• virtualization.deckhouse.io/progress-timeout (default: 150)

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

Previously only parallelOutboundMigrationsPerNode was configurable via a ModuleConfig annotation; the rest of the migration parameters (bandwidthPerMigration, completionTimeoutPerGiB, progressTimeout) were hardcoded in the Helm template. This made it impossible to tune migration performance without patching the module.

The single-parameter hook also duplicated the same pattern (watch ModuleConfig annotations → write to values) that would need to be repeated for every new parameter.

This change unifies all annotation-driven migration settings into one hook and makes the Helm template driven by values, giving operators a clean, documented way to adjust migration performance per cluster.

What is the expected result?

1. Add an annotation to the ModuleConfig for the virtualization module, e.g.:

   kubectl annotate moduleconfig virtualization \
     virtualization.deckhouse.io/bandwidth-per-migration=256Mi \
     virtualization.deckhouse.io/parallel-outbound-migrations-per-node=2

2. Verify the migration-config hook fires and updates the internal values.
3. Verify the KubeVirt CR reflects the new migration settings after Helm re-applies.
4. Remove the annotation and verify the defaults are restored.

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

section: module
type: feature
summary: "Add annotations for configuring KubeVirt migration settings (bandwidth, timeouts, parallelism) via ModuleConfig."
impact_level: low