Add trace tags to task instances and also support OTEL_RESOURCE_ATTRIBUTES for spans

[howardyoo]

closes: #41840

This PR addresses features mentioned in above issue, that OTEL traces will now be able to collect user-defined resources via OTEL_RESOURCE_ATTRIBUTES.

Also, in addition to this, the PR also addresses more complete instrumentation that task instance span will also now contain the tags specified via airflow config's airflow.traces.tags, providing more ways to instrument spans with less user coding involved.

For more information about the OTEL_RESOURCE_ATTRIBUTES, please visit here