feat: add configurable per-user rate limiting for review submissions

[Mridul-Dev123]

(#663)

Change(s)

Change Type: Added

Change Category: Internal

Changelog Entry: Added configurable per-user rate limiting for review submission
requests to prevent users from congesting the review pipeline.

Users are limited to max_submissions_per_user (default: 10) review submission
requests within a rolling submission_window_seconds (default: 3600s = 1 hour)
window. Connector users (platform roles) bypass this limit, as they use the
connector workflow designed for systematic uploads.

The limit values are configurable via config.default.toml or
config.override.toml under the [rate_limits] section.

How to Test

Run the rate limiter unit tests inside Docker:

docker run --rm -v "${PWD}/src:/app" -e KEYCLOAK_CLIENT_SECRET="mocked_secret" \
  --entrypoint sh aiod/metadata_catalogue:local \
  -c "pip install -q pytest && python -m pytest tests/test_review_rate_limit.py -v --noconftest"