otel/trace: forwarding web app OTel traces

Created by: bobheadxi

We have several options here:

• some kind of endpoint in frontend that can forward OTel traces to the configured backend, e.g. an OTel collector instance (ideal)
• otherwise, we have to make OTel collectors available directly, e.g. as described in https://www.honeycomb.io/blog/opentelemetry-browser-instrumentation/
• or the web app has to send traces directly to e.g. Honeycomb

Notes: https://docs.google.com/document/d/1pYgSqJUE9M0_LZFUBzL-5nRTpmbMqXsWCUVU32J-AEo/edit#