[Core V3] Make the bot data path configurable (#879)

* Initial commit

* Fix sentry

* Make cog manager install path work relative to the bot's dir

* Fix downloader to save data relative to the defined data folder

* Fix sentry test

* Fix downloader tests

* Change logfile location

* Add another line to codeowners

* Basic tests

* Fix versioning

* Add in FutureWarning for config file changes

* Add reference to issue

tests/conftest.py

@@ -17,6 +17,13 @@ def monkeysession(request):
     mpatch.undo()
 
 
+@pytest.fixture(autouse=True)
+def override_data_path(tmpdir):
+    from core import data_manager
+    data_manager.basic_config = data_manager.basic_config_default
+    data_manager.basic_config['DATA_PATH'] = str(tmpdir)
+
+
 @pytest.fixture()
 def json_driver(tmpdir_factory):
     import uuid