Enabled detailed Nginx logs for Datadog.

[rudimk]

This PR adds some fixes to the default Helm values for the Datadog addon chart, in order to ensure APM and logging works correctly for workloads across the default, ingress-nginx and custom namespaces. Tests involve running https://github.com/portersupport/datadog-apm-test-python on a test cluster with the addon deployed, with the modified values present in this PR.