516 only tgui (#90397)

## About The Pull Request
oooooh boy, have I been waiting on this PR. It was one of the first
things I tried when I got into 516 alpha. With this, we shuffle off all
the polyfills that makes TGUI build like it's still on IE.

TGUI should look and function exactly the same.

1. updated webpack build targets
2. removed polyfills
3. removed trident references
4. removed trident-only storage
5. updated documentation
6. bumped yarn (sorry, this makes the file diff huge but it seems to be
required)
7. fixed some prettier warnings
## Why It's Good For The Game
TGUI builds without restraint. Smaller bundle size, smaller overhead
## Changelog

🆑
add: TGUI is now v6! No more internet explorer. All gloves are off, it's
running edge under the hood now. Report any issues to the github,
please. Yes, I look!
/🆑

code/controllers/subsystem/tgui.dm

@@ -37,10 +37,6 @@ SUBSYSTEM_DEF(tgui)
 	ntos_error = "<style type='text/css'>\n[ntos_error]\n</style>"
 	basehtml = replacetextEx(basehtml, "<!-- tgui:ntos-error -->", ntos_error)
 
-	// Inject inline polyfills
-	var/polyfill = file2text('tgui/public/tgui-polyfill.min.js')
-	polyfill = "<script type='text/javascript'>\n[polyfill]\n</script>"
-	basehtml = replacetextEx(basehtml, "<!-- tgui:inline-polyfill -->", polyfill)
 	basehtml = replacetextEx(basehtml, "<!-- tgui:nt-copyright -->", "Nanotrasen (c) 2525-[CURRENT_STATION_YEAR]")