feat/OPS-61: added auto documentation for haiku.py, main.py and store_manager.py

At the moment it works by converting senju into a python package. This causes the html docu to start with a link 'senju package' which lists all three moduls and their documentation. I will try now to make it so all three moduls have a docu link of their own.

The method foobar in each modul is for testing purposes and should be deleted once full functionality is confirmed.

senju/store_manager.py

@@ -11,6 +11,11 @@ from senju.haiku import Haiku
 
 DEFAULT_DB_PATH: Path = Path("/var/lib/senju.json")
 
+def foobar():
+    """WE KNOW"""
+    a = 3
+    b = 3
+    return a+b
 
 class StoreManager:
     __slots__ = "_db", "logger"