feat(legacy): Support local BIDS-URIs for IntendedFor fields

[effigies]

Was going to skip validation for the legacy validator for bids-standard/bids-examples#455, but this was pretty straightforward just to fix.

It's not 100% BIDS-URI support, but it is easily over 80% for these fields.

[codecov]

Codecov Report

Attention: Patch coverage is 81.81818% with 2 lines in your changes missing coverage. Please review.

Project coverage is 87.09%. Comparing base (1453bc1) to head (a6a19f8).
Report is 2 commits behind head on master.

Files	Patch %	Lines
...lidator/validators/microscopy/checkJSONAndField.js	83.33%	1 Missing ⚠️
bids-validator/validators/nifti/nii.js	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2069      +/-   ##
==========================================
+ Coverage   85.75%   87.09%   +1.33%     
==========================================
  Files          91      139      +48     
  Lines        3785     6673    +2888     
  Branches     1218     1574     +356     
==========================================
+ Hits         3246     5812    +2566     
- Misses        453      771     +318     
- Partials       86       90       +4     

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