feat: add instance_id metadata to logs

[Draggu]

This allows us to easily grab logs from a single expert run.

Also, make logs single-line where possible for future ease of parsing

[doorgan]

Works as expected, thank you! 💜

==> .expert/expert.log <==
08:57:39.037 instance_id=19C8A5C9B8B [info] Resolved entity: {:call, Rainet, :my_other_fun, 2}
08:57:39.047 instance_id=19C8A5C9B8B [debug] handled request client -> server textDocument/hover in 69ms

==> .expert/project.log <==

08:57:39.037 instance_id=19C8A5C9B8B [info] Resolved entity: {:call, Rainet, :my_other_fun, 2}

==> .expert/expert.log <==
08:57:40.454 instance_id=19C8A5BB43F [debug] handled request client -> server textDocument/codeLens in 11ms
08:57:41.666 instance_id=19C8A5BB43F [info] Resolved entity: {:call, Rainet, :my_other_fun, 2}
08:57:41.683 instance_id=19C8A5BB43F [debug] handled request client -> server textDocument/hover in 99ms

I recall there was a line that turned logs into a single line for "future parsing" but I don't see it anymore. I think removing that was a good call, let's re-add it if necessary in the PR that implements that parsing.

Let's fix the conflicts and I think this is good to go

[mhanberg]

I recall there was a line that turned logs into a single line for "future parsing" but I don't see it anymore

I had said I think it's a readability issue. I believe he removed it after.