some quality of life improvements

[mve]

• Replaced bluebird promise with regular Node.js Promise
• Removed deasync, i believe that package is no longer used?
  This also removes a dependency on Python.
• Updated README.md
• Fixed error in console about i18n "wait"
  https://stackoverflow.com/a/75727176/8678755
• Added steps to check webpack bundle size

Checking the bundle size i noticed that in src/i18n.js, the add-all-tz import adds about 1MB. to the JS, can this be improved?

[codecov]

Codecov Report

Merging #124 (4814c2a) into master (b0d1c12) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #124   +/-   ##
=======================================
  Coverage   96.54%   96.54%           
=======================================
  Files          59       59           
  Lines         955      955           
  Branches      207      207           
=======================================
  Hits          922      922           
  Misses         31       31           
  Partials        2        2           

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[tmoitie]

Thanks for all this!

Checking the bundle size i noticed that in src/i18n.js, the add-all-tz import adds about 1MB. to the JS, can this be improved?

I remember this when I added it that there wasn't much choice, but now I see we could potentially use @formatjs/intl-datetimeformat/add-golden-tz . The risk here is just that it might degrade the experience for users who don't have a "golden" timezone preference, and I don't have the data to figure out the likelyhood of that.