feat(api): split api into multiple apps (#1626)

Fixes #1622

- split the api into 4 apps: core, history, schedule, storage
- exploded the settings into testing/prod

api/libretime_api/models/user_constants.py

@@ -1,11 +0,0 @@
-GUEST = "G"
-DJ = "H"
-PROGRAM_MANAGER = "P"
-ADMIN = "A"
-
-USER_TYPES = {
-    GUEST: "Guest",
-    DJ: "DJ",
-    PROGRAM_MANAGER: "Program Manager",
-    ADMIN: "Admin",
-}