CMRT 25: Analyzer: Add QualityScorer for canonical-track selection

[Swarnadip-Kar]

Adds QualityScorer, a static utility that scores a track's audio quality
for CMRT canonical-track selection (CMRT 27/28 use this to decide which
track in a group of duplicate masterings becomes the canonical reference).

Scoring (Quality_Scoring_Ayush_Proposal.txt)

• Base score by format: FLAC/ALAC/AIFF/WAV = 100/90, down to WMA = 50
• +5 if samplerate > 44100 Hz
• +min(5, filesize / 10MB) as a rough bitrate proxy

Not implemented: the proposal's bit-depth bonus

Bit depth has nowhere to be queried from yet -- it only exists inside
track_analysis's audio_quality JSON blob, written by a fake-lossless
detector that hasn't been built. Adding that bonus now would mean parsing
JSON in this PR for a feature that doesn't exist. Left as a comment in
qualityscorer.cpp pointing at whichever PR adds that detector.

Notes for reviewers

• TrackQualityFields (this PR) and TrackQualityInfo (CMRT 27, in the DAO)
  are two different structs on purpose -- this one is QualityScorer's input
  shape, the other is what TrackFingerprintDao can cheaply SELECT. CMRT 27
  adapts between them.
• The file-size bonus is the weakest term here (conflates bitrate and
  track length) -- flagged in a comment, not fixed, since that's a tuning
  question once this runs against a real library.

Depends on: cmrt-dao-mbid-lookup (#33)

[coveralls]

Coverage Report for CI Build 27872363108

Coverage increased (+0.001%) to 30.438%

Details

• Coverage increased (+0.001%) from the base build.
• Patch coverage: No coverable lines changed in this PR.
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	116230
Covered Lines:	35378
Line Coverage:	30.44%
Coverage Strength:	59259.89 hits per line

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💛 - Coveralls