feat(telemetry): Adding instrumentation around http client for tracing

[tjvkroll]

Summary

This is a feature that adds instrumentation around the http client to enable tracing. Configured a simple trace provider and wrapped the http transport with Open Telemetry instrumentation.

Checklist

• Tested and/or added tests to validate that the changes work as intended, if applicable.
• Updated documentation in README.md, if applicable.

[tjvkroll]

Here is a screenshot of the tracing coming through in Honeycomb showing the value of the full request path through to an endpoint to identify any potential errors:

[tjvkroll]

This testing was done with a local collector container using a http receiver, no encryption, and basic resource attributes being added as example. The env configuration being applied to my Gatus service was as follows:

      - OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=http://localhost:4318/v1/traces
      - OTEL_SERVICE_NAME=gatus
      - OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf
      - OTEL_EXPORTER_OTLP_TRACES_INSECURE=true
      - OTEL_RESOURCE_ATTRIBUTES=deployment.environment=local,service.version=1.0.0

With no env variables in place the exporter will default to http://localhost:4318/v1/traces and will expect and insecure endpoint due to the http prefix. Also no resource attribute will be attached unless specified.