Implement filtering by severity and release channel

This also involves a refactoring of the way reports are encoded: rather than using plaintext error messages, use readable codes and structured metadata for errors and updates to make them easier to process.

️🧪 Test rendering here: https://infrastructure.pages.apertis.org/-/dashboard/-/jobs/1376068/artifacts/public/index.html

Task: https://phabricator.apertis.org/T7889

bin/utils.py

-import collections.abc
+import collections
 import concurrent.futures
 import logging
 import sys
@@ -7,16 +7,14 @@ import sys
 def item_id(item):
     itemid = None
     if logging.root.level <= logging.DEBUG:
-        keys = ("path_with_namespace", "id", "name")
-        for k in keys:
-            if itemid is None:
-                itemid = getattr(item, k, None)
-        for k in keys:
-            if itemid is None and isinstance(item, collections.abc.Mapping):
-                itemid = item.get(k)
+        itemid = getattr(item, "path_with_namespace", None)
+        if itemid is None:
+            itemid = getattr(item, "id", None)
+        if itemid is None:
+            itemid = getattr(item, "name", None)
         if itemid is None and isinstance(item, str):
             itemid = item
-        if itemid is None and isinstance(item, collections.abc.Sequence):
+        if itemid is None and isinstance(item, collections.Sequence):
             itemid = tuple(item_id(i) for i in item)
         if itemid is None:
             itemid = item