feat: add basic support for progress indicators

tests/test_app.py

@@ -12,6 +12,7 @@ import pytest
 
 import wuttjamaican.enum
 from wuttjamaican import app
+from wuttjamaican.progress import ProgressBase
 from wuttjamaican.conf import WuttaConfig
 from wuttjamaican.util import UNSPECIFIED
 
@@ -315,6 +316,19 @@ class TestAppHandler(TestCase):
         uuid = self.app.make_uuid()
         self.assertEqual(len(uuid), 32)
 
+    def test_progress_loop(self):
+
+        def act(obj, i):
+            pass
+
+        # with progress
+        self.app.progress_loop(act, [1, 2, 3], ProgressBase,
+                               message="whatever")
+
+        # without progress
+        self.app.progress_loop(act, [1, 2, 3], None,
+                               message="whatever")
+
     def test_get_session(self):
         try:
             import sqlalchemy as sa