chore(npm): add ignore list

[erisu]

Motivation and Context

• Cleanup the npm package with .npmignore

Description

• Add .npmignore file

Testing

• npm t
• Project
  • cordova create
  • cordova platform add with the cleanup npm package
  • cordova run android
  • cordova build android

Checklist

• I've run the tests to see all new and existing tests pass

[codecov-io]

Codecov Report

Merging #958 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #958   +/-   ##
=======================================
  Coverage   65.53%   65.53%           
=======================================
  Files          21       21           
  Lines        1828     1828           
=======================================
  Hits         1198     1198           
  Misses        630      630           

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