[DO NOT MERGE] WIP: wasmtime shim OpenTelemetry tracing support

[Mossaka]

This PR introduces OpenTelemetry feature and new APIs on the core crate to add tracing capabilities to the shim.

• Added OpenTelemetry tracing to the main entry point of the shim. It now parses the OTEL_EXPORTER_OTLP_ENDPOINT environment variable to determine if the shim should be started with OpenTelemetry tracing.
• Enable that in the wasmtime shim

It builds on top of #564