Optimize randomBytes

[ghost]

Description

This PR refactors and optimizes randomBytes().

• For browser or web worker environment, use window.crypto.getRandomValues()
• For node environment, we use sodium-native to generate random bytes safely
• by dropping sodium-universal, we can minimize dependency and the bundle size (32kb -> 1.3kb when Minified + Gzipped) and still support web worker environment.
• handles the limit of getRandomValues() which is about the requested length.
• supports IE 11

Also, this PR upgrades @types/node & prettier and formats codes in order to use optional chaining without errors.

References

• https://github.com/sodium-friends/sodium-javascript/blob/master/randombytes.js
• https://github.com/crypto-browserify/randombytes/blob/master/browser.js
• https://github.com/flexdinesh/browser-or-node
• https://paragonie.com/blog/2016/05/how-generate-secure-random-numbers-in-various-programming-languages#nodejs-csprng
• https://paragonie.com/blog/2016/05/how-generate-secure-random-numbers-in-various-programming-languages#js-csprng

Motivation and Context

How has this been tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• Add tests to cover changes as needed.
• Update documentation as needed.

[codecov-commenter]

Codecov Report

Merging #345 (8ea40ca) into dev (0260567) will decrease coverage by 0.13%.
The diff coverage is 76.19%.

❗ Current head 8ea40ca differs from pull request most recent head cc24749. Consider uploading reports for the commit cc24749 to get more accurate results

@@            Coverage Diff             @@
##              dev     #345      +/-   ##
==========================================
- Coverage   80.80%   80.67%   -0.14%     
==========================================
  Files          44       44              
  Lines        1782     1790       +8     
  Branches      294      298       +4     
==========================================
+ Hits         1440     1444       +4     
- Misses        341      345       +4     
  Partials        1        1              

Impacted Files	Coverage Δ
packages/zilliqa-js-core/src/net.ts	98.59% <ø> (ø)
packages/zilliqa-js-crypto/src/random.ts	75.00% <64.28%> (-15.91%)	⬇️
packages/zilliqa-js-account/src/transaction.ts	90.20% <100.00%> (ø)
packages/zilliqa-js-account/src/wallet.ts	82.03% <100.00%> (-0.14%)	⬇️
packages/zilliqa-js-blockchain/src/chain.ts	62.92% <100.00%> (ø)
packages/zilliqa-js-crypto/src/util.ts	82.45% <100.00%> (ø)
packages/zilliqa-js-subscriptions/src/ws.ts	64.96% <100.00%> (ø)
packages/zilliqa-js-util/src/unit.ts	80.95% <100.00%> (ø)

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[teye]

Good! Works with the examples! No issues on react.

[bb111189]

LGTM