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/packaging-data-fetch-downstream

@@ -4,7 +4,6 @@ from __future__ import annotations
 
 import argparse
 import fnmatch
-import itertools
 import logging
 import urllib.parse
 
@@ -192,21 +191,6 @@ class DownstreamFetcher:
         thread_pool(num_worker_threads, _fetch_license_report, projects, num_retries=2)
 
 
-def check_duplicates(projects, data):
-    def packagenamefunc(p):
-        return p.packagename
-
-    for packagename, projects in itertools.groupby(
-        sorted(projects, key=packagenamefunc), packagenamefunc
-    ):
-        paths = [p.path_with_namespace for p in projects]
-        if len(paths) == 1:
-            continue
-        msg = f"Project name '{packagename}' is ambiguous across projects: {', '.join(paths)}"
-        logging.error(msg)
-        data["packages"][packagename].setdefault("errors", []).append({"msg": msg})
-
-
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(
         description="Fetch data from the GitLab packaging projects"
@@ -270,6 +254,4 @@ if __name__ == "__main__":
         "channels": d.channels,
     }
 
-    check_duplicates(d.projects, data)
-
     yaml.dump(data, args.yaml, width=120, Dumper=yaml.CSafeDumper)