Add npm package for the docgen-tool

[SupunS]

Description

Bundle the docgen-tool WASM as an NPM package.

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• Targeted PR against master branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work
• Code follows the standards mentioned here
• Updated relevant documentation
• Re-reviewed Files changed in the Github PR explorer
• Added appropriate labels

[codecov-commenter]

Codecov Report

Merging #1008 (e60345b) into master (d2fc5d7) will not change coverage.
The diff coverage is n/a.

❗ Current head e60345b differs from pull request most recent head 87a317b. Consider uploading reports for the commit 87a317b to get more accurate results

@@           Coverage Diff           @@
##           master    #1008   +/-   ##
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  Coverage   75.58%   75.58%           
=======================================
  Files         267      267           
  Lines       32885    32885           
=======================================
  Hits        24856    24856           
  Misses       6908     6908           
  Partials     1121     1121           

Flag	Coverage Δ
unittests	75.58% <ø> (ø)

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[turbolent]

Nice!

Great this comes with a test 👍 Once merged we can publish it 🙁

Just one minor ask: Could you please add the package.json here https://github.com/onflow/cadence/blob/master/Makefile#L77? This way we can keep it updated