Further tidyups + refactoring for new structure

* Add implementation tests for orchestrator + logging tests
* Standardise method/class vars for extractors to see if they are suitable
* Fix bugs with removing default loguru logger (allows further customisation)
* Fix bug loading required fields from file
*

tests/data/test_modules/example_module/__manifest__.py

@@ -0,0 +1,11 @@
+{
+    "name": "Example Module",
+    "type": ["extractor", "feeder", "formatter", "storage", "enricher", "database"],
+    "requires_setup": False,
+    "dependencies": {"python": ["loguru"]
+                              },
+    "configs": {
+            "csv_file": {"default": "db.csv", "help": "CSV file name"},
+            "required_field": {"required": True, "help": "required field in the CSV file"},
+        },
+}