Added QR code generation

[joshterrill]

This is in place of https://github.com/webtorrent/instant.io/pull/104

And uses the kjua library that was recommended in https://github.com/webtorrent/instant.io/issues/94

[joshterrill]

@feross The standard test is failing on the ci because I'm using location as a means of getting the domain that instant.io is running on, and location is not specifically defined anywhere. Is there a better way of getting the current domain in this app?

[willstott101]

You have to use window.location to make standard happy.

[kaotisk-hund]

Hi everyone, I see on my tests that node v18 passes the test while v14 doesn't. Log output:

standard: Unexpected linter output:                                                                                                            [70/529]
                                                                           
Error: EACCES: permission denied, scandir '/proc/tty/driver'                                                                                           
    at Object.readdirSync (fs.js:1048:3)                                                                                                               
    at readdirSafeSync (/node_modules/eslint/lib/cli-engine/file-enumerator.js:140:19)                                                                 
    at FileEnumerator._iterateFilesRecursive (/node_modules/eslint/lib/cli-engine/file-enumerator.js:434:29)                                           
    at _iterateFilesRecursive.next (<anonymous>)                           
    at FileEnumerator._iterateFilesRecursive (/node_modules/eslint/lib/cli-engine/file-enumerator.js:487:33)                                           
    at _iterateFilesRecursive.next (<anonymous>)                           
    at FileEnumerator._iterateFilesRecursive (/node_modules/eslint/lib/cli-engine/file-enumerator.js:487:33)                                           
    at _iterateFilesRecursive.next (<anonymous>)                           
    at FileEnumerator._iterateFilesRecursive (/node_modules/eslint/lib/cli-engine/file-enumerator.js:487:33)                                           
    at _iterateFilesRecursive.next (<anonymous>)                           
                                                                           
If you think this is a bug in `standard`, open an issue: https://github.com/standard/standard/issues                                                   
npm ERR! Test failed.  See above for more details.

This is reproduced with the window.location.origin, under docker.io/library/node:14 using podman as container.