Add more invoke commands:

- export-records: Exports all database records to external file
- import-records: Imports database records from external file
- import-fixtures: Fills the database with dummy records

InvenTree/common/fixtures/currency.yaml

@@ -1,16 +0,0 @@
-# Test fixtures for Currency objects
-
-- model: common.currency
-  fields:
-    symbol: '$'
-    suffix: 'AUD'
-    description: 'Australian Dollars'
-    base: True
-
-- model: common.currency
-  fields:
-    symbol: '$'
-    suffix: 'USD'
-    description: 'US Dollars'
-    base: False
-    value: 1.4