test: each app keeps its tests in a tests package

131 test modules sat next to the code they test; instances alone had
51 of them beside views.py and utils.py. They move into a
tests/ package per app, and the JavaScript checks into
webvirtcloud/tests/js. Each non-empty tests.py becomes tests/test_views.py;
the empty generated stubs are removed.

Imports of the app's own modules become absolute, paths built from
__file__ go one level up, the live helper is instances.tests.livetest,
and coverage omits */tests/*. The suite discovers the same 960 tests as
before.

appsettings/test_appsettings.py

@@ -1,50 +0,0 @@
-from django.test import RequestFactory, TestCase
-from django.urls import reverse
-
-from appsettings.models import AppSettings
-from appsettings.settings import app_settings, get_settings
-
-
-class AppSettingsTestCase(TestCase):
-    def setUp(self):
-        self.client.login(request=RequestFactory().get("/"), username="admin", password="admin")
-
-    def test_get_settings_populates_singleton(self):
-        AppSettings.objects.update_or_create(
-            key="CUSTOM_TEST_SETTING",
-            defaults={"value": "test_value_123", "name": "Custom Test Setting"}
-        )
-        get_settings()
-        self.assertEqual(getattr(app_settings, "CUSTOM_TEST_SETTING", None), "test_value_123")
-
-    def test_appsettings_view_get(self):
-        response = self.client.get(reverse("appsettings"))
-        self.assertEqual(response.status_code, 200)
-
-    def test_appsettings_update_setting(self):
-        setting = AppSettings.objects.get(key="SHOW_ACCESS_ROOT_PASSWORD")
-        original_value = setting.value
-        new_val = "False" if original_value == "True" else "True"
-
-        response = self.client.post(
-            reverse("appsettings"),
-            {
-                "SHOW_ACCESS_ROOT_PASSWORD": new_val
-            }
-        )
-        self.assertRedirects(response, reverse("appsettings"))
-
-        setting.refresh_from_db()
-        self.assertEqual(setting.value, new_val)
-
-    def test_appsettings_non_superuser_forbidden(self):
-        from django.contrib.auth.models import User
-        regular_user = User.objects.create_user(username="regular", password="pwd")
-        self.client.force_login(regular_user)
-        response = self.client.get(reverse("appsettings"))
-        self.assertEqual(response.status_code, 403)
-
-    def test_clones_are_not_migrated_automatically(self):
-        # a clone stays on the host of the VM it was made from; the setting
-        # that sent it to a random host is removed by migration 0015
-        self.assertFalse(AppSettings.objects.filter(key="CLONE_INSTANCE_AUTO_MIGRATE").exists())