Create default EE in seperate awx-managment cmd

Create EE at a seperate time and also attach a registry credential if
auth information provided

This command can be run multiple times on the same instance and should be
idempotent.

awx/main/management/commands/create_preload_data.py

@@ -2,9 +2,8 @@
 # All Rights Reserved
 
 from django.core.management.base import BaseCommand
-from django.conf import settings
 from crum import impersonate
-from awx.main.models import User, Organization, Project, Inventory, CredentialType, Credential, Host, JobTemplate, ExecutionEnvironment
+from awx.main.models import User, Organization, Project, Inventory, CredentialType, Credential, Host, JobTemplate
 from awx.main.signals import disable_computed_fields
 
 
@@ -68,13 +67,6 @@ class Command(BaseCommand):
                     print('Demo Credential, Inventory, and Job Template added.')
                     changed = True
 
-                for ee in reversed(settings.DEFAULT_EXECUTION_ENVIRONMENTS):
-                    _, created = ExecutionEnvironment.objects.update_or_create(name=ee['name'], defaults={'image': ee['image'], 'managed_by_tower': True})
-
-                if created:
-                    changed = True
-                    print('Default Execution Environment(s) registered.')
-
         if changed:
             print('(changed: True)')
         else: