#5850 - Add QR code to API credentials

This uses https://github.com/jeromeetienne/jquery-qrcode for generating
the QR code.

This is what it looks like:

![see screen shot](http://cld.wthms.co/11wpb+)

It’s small, **but**, it scans perfectly without any issues.
Only enqueue/localize on profile page
merge changes
Merge pull request #6802 from bryceadams/patch-5850

#5850 - Add QR code to API credentials