tracing not available in the audit service

## Describe the bug
Configuration for tracing is available, but it isn't set up. This is mostly for events.
Metadata propagation for events is also missing.

Since this is an "end" service which doesn't use any other service, I guess it's fine for now. The audit service doesn't use contextual metadata at the moment.

## Steps to reproduce
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## Expected behavior
We should have information about what happens in the audit service.
Contextual metadata should be available in the service.

## Actual behavior
No trace is generated for this service.

## Setup
Please describe how you started the server and provide a list of relevant environment variables or configuration files.

```console
OCIS_XXX=somevalue
OCIS_YYY=somevalue
PROXY_XXX=somevalue
```

## Additional context
Add any other context about the problem here.