[V3 Config] Fix unloading and implement singleton driver (#1458)

* Add the identifier as an initialization parameter

* Remove config object singleton and opt for a shared JSON datastore

* Fix bot unloading to deal with memory leaks

* Fix tests

* Fix clear all bug

tests/core/test_config.py

@@ -298,6 +298,16 @@ async def test_member_clear_all(config, member_factory):
     assert len(await config.all_members()) == 0
 
 
+@pytest.mark.asyncio
+async def test_clear_all(config):
+    await config.foo.set(True)
+    assert await config.foo() is True
+
+    await config.clear_all()
+    with pytest.raises(KeyError):
+        await config.get_raw('foo')
+
+
 @pytest.mark.asyncio
 async def test_clear_value(config):
     await config.foo.set(True)