Add logging functions to support third party apps

[mayhem]

Right now all output about scanning a subsonic collection goes to stdout, which is worthless for a web app like lb-local. Naming the logger and adding a new logging level that this output goes to allows third parties to tap into better logging facilities in troi.

[github-actions]

Test Results

  4 files  ±0    4 suites  ±0   4s ⏱️ ±0s
 50 tests ±0   50 ✅ ±0  0 💤 ±0  0 ❌ ±0 
200 runs  ±0  200 ✅ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit 0fcc5a3. ± Comparison against base commit 7a1a98d.

♻️ This comment has been updated with latest results.

[github-actions]

Package	Line Rate	Complexity	Health
.	33%	0	❌
content_resolver	0%	0	❌
content_resolver.formats	6%	0	❌
content_resolver.model	0%	0	❌
external	39%	0	❌
listenbrainz	46%	0	❌
musicbrainz	72%	0	➖
patches	27%	0	❌
patches.lb_radio_classes	0%	0	❌
tools	20%	0	❌
.	33%	0	❌
content_resolver	0%	0	❌
content_resolver.formats	6%	0	❌
content_resolver.model	0%	0	❌
external	39%	0	❌
listenbrainz	46%	0	❌
musicbrainz	72%	0	➖
patches	27%	0	❌
patches.lb_radio_classes	0%	0	❌
tools	20%	0	❌
.	33%	0	❌
content_resolver	0%	0	❌
content_resolver.formats	6%	0	❌
content_resolver.model	0%	0	❌
external	39%	0	❌
listenbrainz	46%	0	❌
musicbrainz	72%	0	➖
patches	27%	0	❌
patches.lb_radio_classes	0%	0	❌
tools	20%	0	❌
.	33%	0	❌
content_resolver	0%	0	❌
content_resolver.formats	6%	0	❌
content_resolver.model	0%	0	❌
external	39%	0	❌
listenbrainz	46%	0	❌
musicbrainz	72%	0	➖
patches	27%	0	❌
patches.lb_radio_classes	0%	0	❌
tools	20%	0	❌
Summary	21% (4283 / 20130)	0	❌

[amCap1712]

I don't think you should need the manual isEnabledFor, the logger module will check it internally. Also for the next line, why not use log?

[mayhem]

log throws argument conversion errors, so sticking with _log, which works.