Make println utility reusable

[Neverlord]

Moves the println utility from the broker-node to the internal namespace to allow us to re-use this in other tools and benchmarks.

[Neverlord]

@timwoj did maybe something in btest change recently? I see tons of btest suites failing on CI but this PR doesn't even touch anything remotely related to them. 🤨

[awelzel]

I see tons of btest suites failing on CI but this PR doesn't even touch anything remotely related to them. raised_eyebrow

Downloading the artifacts for Fedora 37 and opening a few .stderr files, it looks like the broker-node process involved in the tests is segfaulting:

  1 <<< [7391] broker-node --config-file=../node.cfg                                
  2 /root/.local/bin/btest-bg-run-helper: line 25:  7393 Segmentation fault      (core dumped) broker-node --config-file=../node.cfg
  3 >>>                                                                             
  4 <<< [7451] python3 ../recv.py >recv.out                                         
  5 failed to connect to ws://localhost:1045/v1/messages/json, try again            
  ...

  1 <<< [5233] broker-node --config-file=../node.cfg                                
  2 /root/.local/bin/btest-bg-run-helper: line 25:  5235 Segmentation fault      (core dumped) broker-node --config-file=../node.cfg
  3 >>>                                                                             
  4 >>> process 5233 failed with exitcode 139: broker-node --config-file=../node.cfg

[Neverlord]

Downloading the artifacts for Fedora 37 and opening a few .stderr files, it looks like the broker-node process involved in the tests is segfaulting:

🤦‍♂️

Sorry for the noise, should've checked myself.