Implement VM provision locking mechanism and enhance VM job handling

app/Models/VmProvisionLock.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+
+class VmProvisionLock extends Model
+{
+    protected $fillable = ['customer_id', 'order_item_id', 'status'];
+
+    public static function isRunning(int $customerId): bool
+    {
+        return static::where('customer_id', $customerId)->where('status', 'running')->exists();
+    }
+}