Added 'instances:clone_instances' permission

Replaces 'can_clone_instances' user attribute

instances/migrations/0002_permissionset.py

@@ -0,0 +1,24 @@
+# Generated by Django 2.2.12 on 2020-05-27 07:01
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('instances', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='PermissionSet',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+            ],
+            options={
+                'permissions': (('clone_instances', 'Can clone instances'),),
+                'managed': False,
+                'default_permissions': (),
+            },
+        ),
+    ]