Seperate proxy port for debug endpoints

# Current state

Every service has its own debug port (e.g. storage-users 9159) to provide routes for `metrics`, `healthz` and `readyz`.

# Proposal

Have an additional port opened by the proxy (e.g. 62000) where all those endpoints can be seperately accesses through a generic route like

`https://your.tld:9100/services//`

**Examples:**

- `https://your.tld:62000/services/storage-users/metrics`
- `https://your.tld:62000/services/storage-users/healthz`
- `https://your.tld:62000/services/storage-users/readyz`

# Benefit

All metrics endpoints would be available through a generic path and can be accessed from external monitoring without having to open all debug ports on the cluster. It would also be possible to route this through an reverse proxy and secure it by other means there (e.g. basic-auth).

**Note:** This is post 3.0.0