Update demo data hook to copy media files (#3441)

* Simplify settings.py / config.py

- get_setting function has been streamlined
- move some functions into config.py

* Spelling fix: IGNORRED is IGNORED

* Ensure yaml is installed as part of docker image

- invoke path is still mucking us around

* Fix broken migration

* Copy media files from demo dataset when installing test data

* Cleanup settings.py

* Fix for configuration file traversal

* Line fix

* Update quickstart guide for docker

* Allow plugin file and plugin dir to be specified in configuration file

* Cleanup config template file

* Allow secret_key information to be provided in configuration file

* Adjust root paths for CI tests

* resolve paths

* Revert paths for CI step

* remove dead code

* Revert configuration variables to old names

- Prevent breaking changes

* Simplify secret key generation

* Fix default timeout for background worker process

* Revert change for customization options

InvenTree/common/migrations/0010_migrate_currency_setting.py

@@ -2,12 +2,12 @@
 
 from django.db import migrations
 from common.models import InvenTreeSetting
-from InvenTree.settings import get_setting, CONFIG
+from InvenTree.config import get_setting
 
 def set_default_currency(apps, schema_editor):
     """ migrate the currency setting from config.yml to db """
     # get value from settings-file
-    base_currency = get_setting('INVENTREE_BASE_CURRENCY', CONFIG.get('base_currency', 'USD'))
+    base_currency = get_setting('INVENTREE_BASE_CURRENCY', 'base_currency', 'USD')
     # write to database
     InvenTreeSetting.set_setting('INVENTREE_DEFAULT_CURRENCY', base_currency, None, create=True)