Added sxi (xlsx-import-cli) examples

[Siemienik]

Resolves how to use xlsx-import-cli from #6

[codecov]

Codecov Report

Merging #129 (d43aba3) into master (5d1fb0f) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master      #129   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           51        51           
  Lines          967       967           
  Branches       134       134           
=========================================
  Hits           967       967           

Flag	Coverage Δ
xlsx-import	100.00% <ø> (ø)
xlsx-renderer	100.00% <ø> (ø)

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