restructure waveplot output

[BryonLewis]

I didn't want to pollute the raw compressed/uncompressed paths that may be a list of images with having to parse each filename and look for keywords.

I attempted to swap to waveplot.path and waveplot.compressed.path as higher level key's in the spectrogram object to indicate the arrays.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 57.6%. Comparing base (5e04bc7) to head (c8438bc).
⚠️ Report is 3 commits behind head on tas/update-metadata.

Additional details and impacted files

@@                 Coverage Diff                 @@
##           tas/update-metadata     #40   +/-   ##
===================================================
  Coverage                 57.6%   57.6%           
===================================================
  Files                        7       7           
  Lines                     1321    1322    +1     
===================================================
+ Hits                       761     762    +1     
  Misses                     560     560           

Files with missing lines	Coverage Δ
batbot/spectrogram/__init__.py	68.8% <100.0%> (+<0.1%)	⬆️

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[stoutta6]

LGTM