Prevent uWSGI from consuming too much memory (#2884)

# What this PR does

Fixes https://github.com/grafana/oncall/issues/1521 (see
https://github.com/unbit/uwsgi/issues/2299)

## Checklist

- [x] Unit, integration, and e2e (if applicable) tests updated
- [x] Documentation added (or `pr:no public docs` PR label added if not
required)
- [x] `CHANGELOG.md` updated (or `pr:no changelog` PR label added if not
required)

engine/uwsgi.ini

@@ -95,6 +95,9 @@ die-on-term=true
 ; every request. It is not so slow, but with some kind of app/extensions that could be overkill.
 single-interpreter=true
 
+; Prevent uWSGI from consuming too much memory: https://github.com/grafana/oncall/issues/1521
+max-fd=1048576
+
 logger=stdio
 log-format=source=engine:uwsgi status=%(status) method=%(method) path=%(uri) latency=%(secs) google_trace_id=%(var.HTTP_X_CLOUD_TRACE_CONTEXT) protocol=%(proto) resp_size=%(size) req_body_size=%(cl)
 log-encoder=format ${strftime:%%Y-%%m-%%d %%H:%%M:%%S} ${msgnl}