NGINX OTEL: support TLS, headers, and resource attributes

[sjberman]

With the 0.1.2 release of the nginx OTEL module, new capabilities have been added. We should allow users to take advantage of these capabilities.

https://github.com/nginxinc/nginx-otel/releases/tag/v0.1.2

Specifically,

• ability to set custom headers
• ability to enable TLS trace exports
• ability to set custom resource attributes