feat(cli): add multi lifecycle operations with label-selector and confirmation prompt

[yaroslavborbat]

Description

Add support for multi-target lifecycle operations, label-selector targeting, and confirmation prompts in the CLI (d8v).

• Lifecycle commands (start, stop, restart, evict, migrate) now accept multiple VM names as arguments.
• New --all flag applies the operation to all VMs in the current namespace.
• New --label-selector / -l flag filters target VMs by label set (e.g. --label-selector env=prod,tier=frontend).
• New --yes / -y flag skips interactive confirmation; without it, each VM requires explicit y/yes confirmation before the action is executed.
• --all and --label-selector are mutually exclusive; both are incompatible with positional VM name arguments.
• When operating on multiple VMs, --create-only is implicitly forced to prevent blocking on each individual operation.
• Errors and messages per VM are printed inline instead of aborting the whole batch.

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

Previously, lifecycle commands only accepted a single VM name, requiring users to run the command repeatedly for each VM.
This is inconvenient in scenarios like draining a node, performing maintenance, or bulk-testing VM lifecycle behaviour.
The --all flag and multi-argument support eliminate the need for shell loops.
The --label-selector flag allows targeting a logical group of VMs without listing each one explicitly.
The confirmation prompt prevents accidental bulk operations, while --yes keeps scripting ergonomic.

What is the expected result?

1. Run d8v stop vm1 vm2 vm3 — all three VMs are stopped (with per-VM confirmation).
2. Run d8v restart --all --yes — all VMs in the current namespace are restarted without prompting.
3. Run d8v stop --label-selector env=prod — stops all VMs matching the label, with per-VM confirmation.
4. Run d8v start --all vm1 — command returns an error: cannot use --all with specific keys.
5. Run d8v start --all --label-selector env=prod — command returns an error: cannot use both flags together.

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: core
type: feature
summary: "CLI lifecycle commands (start, stop, restart, evict, migrate) now support multiple VM targets, --all flag, --label-selector flag for label-based targeting, and --yes flag for non-interactive confirmation."