Fix --derivedDataPath not working properly and renaming CLI option to --dataStorePath

[Nikoloutsos]

Found some time to work a little more on that tool. This PR will 👇

• Fix bug where --derivedDataPath was broken and was returning empty results to user.
• Rename --derivedDataPath to --dataStorePath to better reflect what the option does.
• Updated the Skill and the Readme file.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 74.57627% with 15 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.01%. Comparing base (cbc8c9f) to head (668ee8e).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...ndRefs/CompositionRoot/RemoveCompositionRoot.swift	58.33%	5 Missing ⚠️
...efs/DerivedData/DataStorePathValidationError.swift	0.00%	4 Missing ⚠️
Sources/SwiftFindRefs/SwiftFindRefs.swift	0.00%	4 Missing ⚠️
...ndRefs/CompositionRoot/SearchCompositionRoot.swift	80.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master       #9      +/-   ##
==========================================
- Coverage   93.62%   93.01%   -0.61%     
==========================================
  Files          33       34       +1     
  Lines        2054     2019      -35     
==========================================
- Hits         1923     1878      -45     
- Misses        131      141      +10     

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