new applets app for cross-board usage of Applet() & UserApplet() models; dashboard migrations reset and apps reseeded w. new default specs; core.settings & many tests thru-out suite updated accordingly

src/apps/dashboard/tests/integrated/test_views.py

@@ -5,11 +5,12 @@ from django.test import override_settings, TestCase
 from django.urls import reverse
 from django.utils import html
 
+from apps.applets.models import Applet, UserApplet
 from apps.dashboard.forms import (
     DUPLICATE_ITEM_ERROR,
     EMPTY_ITEM_ERROR,
 )
-from apps.dashboard.models import Applet, Item, List, UserApplet
+from apps.dashboard.models import Item, List
 from apps.lyric.models import User