Make the necessary changes to the models

- remove InstanceGroup.controller
- remove Instance.last_isolated_check
- remove .is_isolated and .is_controller methods/properties
- remove .choose_online_controller_node() method
- remove .supports_isolation() and replace with .can_run_containerized
- simplify .can_run_containerized

awx/main/migrations/0139_isolated_removal.py

@@ -0,0 +1,26 @@
+# Generated by Django 2.2.16 on 2021-04-21 15:02
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main', '0138_custom_inventory_scripts_removal'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='instance',
+            name='last_isolated_check',
+        ),
+        migrations.RemoveField(
+            model_name='instancegroup',
+            name='controller',
+        ),
+        migrations.AlterField(
+            model_name='unifiedjob',
+            name='controller_node',
+            field=models.TextField(blank=True, default='', editable=False, help_text='The instance that managed the execution environment.'),
+        ),
+    ]