prs-fleshgolem-2070: feat: sqlalchemy 2.0 (#2096)

* upgrade sqlalchemy to 2.0

* rewrite all db models to sqla 2.0 mapping api

* fix some importing and typing weirdness

* fix types of a lot of nullable columns

* remove get_ref methods

* fix issues found by tests

* rewrite all queries in repository_recipe to 2.0 style

* rewrite all repository queries to 2.0 api

* rewrite all remaining queries to 2.0 api

* remove now-unneeded __allow_unmapped__ flag

* remove and fix some unneeded cases of "# type: ignore"

* fix formatting

* bump black version

* run black

* can this please be the last one. okay. just. okay.

* fix repository errors

* remove return

* drop open API validator

---------

Co-authored-by: Sören Busch <fleshgolem@gmx.net>

tests/integration_tests/user_group_tests/test_group_mealplan.py

@@ -85,7 +85,6 @@ def test_crud_mealplan(api_client: TestClient, unique_user: TestUser):
 
 
 def test_get_all_mealplans(api_client: TestClient, unique_user: TestUser):
-
     for _ in range(3):
         new_plan = CreatePlanEntry(
             date=date.today(),