feat: improve on api structure, add openapi tags (#2295)

this logically groups api endpoints and gioves them specific openapi tags. which makes them nice on the `/docs` endpoint and makes the `api.py` more approachable
* add wallets list endpoint
* remove trailing slashes from endpoints
* fixup topup url
* fix trailing slash on auth
* backwards compatibility

lnbits/app.py

@@ -43,7 +43,7 @@ from .commands import migrate_databases
 from .core import init_core_routers
 from .core.db import core_app_extra
 from .core.services import check_admin_settings, check_webpush_settings
-from .core.views.api import add_installed_extension
+from .core.views.extension_api import add_installed_extension
 from .core.views.generic import update_installed_extension_state
 from .extension_manager import (
     Extension,