Add func parseWorksheetPathsAndNames on XLSXFile

[MaxDesiatov]

Resolve #105.

[codecov]

Codecov Report

Merging #109 into master will increase coverage by 0.12%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #109      +/-   ##
==========================================
+ Coverage   97.21%   97.33%   +0.12%     
==========================================
  Files           8        8              
  Lines         287      300      +13     
==========================================
+ Hits          279      292      +13     
  Misses          8        8              

Impacted Files	Coverage Δ
Sources/CoreXLSX/XLSXFile.swift	97.54% <100.00%> (+0.29%)	⬆️

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