Default Liveness and Readiness endpoints return 404

[davidpellcb]

I found this earlier issue but it's closed. Given the existence of default liveness and readiness endpoints that are URL paths, it'd be nice if ping-style healthchecks were added by default. It takes some digging to see that, despite the existence of default HTTP endpoints that get registered in the manager options by default, you need to add handlers manually or use a TCP check.