Remove support for IE11

[zepumph]

Today we decided to remove support of IE11. Wahoo!

We will want to do the following work:

• Make a notification Create a message that we don't support IE 11 chipper#954
• Update QA processes to not test QA.
• Remove workarounds already in place
  • remove polyfills like es6-promise-1e68dc.auto.min.js
  • remove polyfills like mdn-array-from-polyfill.js.
  • Remove Client.errorIfIE.
  • Client.js:156 workaround
  • I'm sure there are others
  • 14 remaining usages of platform.ie in scenery. Those are likely workarounds.
  • 35 usages of IE11 as a whole word.
  • Usage of "Internet Explorer" in WaveInterferenceControlPanel.js
  • Usage of "Internet Explorer" in initialize-globals for `?forceStubbedAudioContext"
  • Replace %1===0 with Number.isInteger, see Replace %1===0 with Number.isInteger #1039
  • Use string.includes
  • Use string.startsWith
  • replace Utils.sign with Math.sign, deprecate (or remove) Utils.sign.
• Update CRC about IE specific workarounds
• Remove IE11 target from transpile.js, see Remove IE 11 from transpile.js chipper#963
• Brainstorm as a dev team if there are obvious methods/features that people will start using now but haven't been able (i.e. String.endsWith). It would be nice to be on the same page as a group.
• Better way to run QSM: Use URLSearchParams after we drop IE support query-string-machine#36
• MutableOptionsNode says it can use Reflect.construct when IE11 support is dropped.
• @jonathanolson wants to be assigned to look into scenery workarounds for IE11
• Add a checklist item to the CRC that says something like "remove any specific workaround for IE11. It is vestigial and doesn't need to be there!"

We can continue to add to this list during dev meeting discussion

[chrisklus]

from 06/18/20 dev meeting:

One part we brought up is that it would be nice for us to use built-in versions of utility functions like String.endsWith and Array.includes instead of the lodash versions going forward.

For now, we're not going to replace existing lodash usages that have built-in counterparts, but will keep that big shift as an option for the future if we find it annoying that there's occurrences of both.

As a general rule for IE workarounds, @ariel-phet says feel free to remove anything that's in the way or annoying, but no need to carefully go through and remove stuff that's not intrusive.

[samreid]

I addressed several parts in the commits above. I did not want to take the time to convert all string.indexOf to string.includes or string.startsWith, so I added that to the CRC. The remaining work for this issue is:

• 14 remaining usages of platform.ie in scenery. Those are likely workarounds.
• 35 usages of IE11 as a whole word, many for a Stencil support
• @jonathanolson wants to be assigned to look into scenery workarounds for IE11

Leaving assigned to @jonathanolson for these final steps.