chore(deps): Modernize some dependencies

[dpogue]

Platforms affected

iOS

Motivation and Context

This allows us to drop the fs-extra and unorm library by replacing their use with built-in NodeJS standard library calls.

Description

• Replace unorm module with String.prototype.normalize
• Replace fs-extra usage with equivalent NodeJS fs calls
• Upgrade which to latest version
• Use path.join in a bunch of spots where we're constructing paths
• Remove the (unused) nopt dependency

Testing

• Existing unit tests pass
• Created and built iOS test project

Checklist

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

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 86.56716% with 9 lines in your changes are missing coverage. Please review.

Project coverage is 78.47%. Comparing base (1974dbb) to head (7ddec78).

Files	Patch %	Lines
lib/prepare.js	75.00%	3 Missing ⚠️
lib/run.js	50.00%	3 Missing ⚠️
lib/Api.js	75.00%	1 Missing ⚠️
lib/build.js	85.71%	1 Missing ⚠️
lib/plugman/pluginHandlers.js	92.85%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1413      +/-   ##
==========================================
- Coverage   78.50%   78.47%   -0.03%     
==========================================
  Files          16       16              
  Lines        1814     1812       -2     
==========================================
- Hits         1424     1422       -2     
  Misses        390      390              

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[erisu]

LGTM