Instrument the faucet

[Mirko-von-Leipzig]

The faucet currently emits events/logs but no open-telemetry spans.

• Add an enable-otel cli arg in the same fashion as the node.
• Instrument the various endpoints.

I would advise reading the node documentation chapter on open-telemetry.

Especially the tokens endpoint should be split into logical spans for the duration of the request so that one can make sense of which parts are slow.

This includes spans for locking any shared state etc.

For inspiration, take a look at the block and batch building in the block-producer. As a general rule, prefer spans over events.

[Mirko-von-Leipzig]

Another thing to consider is not overloading the stdout logs.

[SantiagoPittella]

@sergerad can we consider this as completed by #834 ?

[bobbinth]

@sergerad - I think you mentioned that there is more work to be done here. Should we update the issue and move it to the next milestone?

[sergerad]

The changes from my commit seem to be gone in next now. This will have to be redone so we should move it to the next milestone.

I can't see these diffs anymore in next:
https://github.com/0xMiden/miden-node/pull/834/files

[sergerad]

Looks like some functions were moved around and some deleted. In any case will have to rehash for next milestone.