Wt

In #11705 we have added a library to generate QR codes.
This library is shipped with Wt, but needs to be called manually by developers.

Often the encoded value will hold a specific reference to the use-case it is tied to. For example, sharing a QR code for WiFi access will result in a format of WIFI:S:<SSID>;T:<WEP|WPA|nopass>;P:<PASSWORD>;H:<true|false|blank>;;.
Likewise otp has its own format specified for this as well, as do many others.

We would not implement all possible standards here, but look for a nice middle ground.
We simply accept a string, that the developer may or may not have used to encode data in.

The error level correction, and the size of the grid need to be specified. For these we can add some defaults, but they ought to be configurable.