Proto commits in mono0926/barcode_scan2

These 6 commits are when the Protocol Buffers files have changed:

Commit:61ef192
Author:Vipin Kashyap

Updates kotlin version, regenerate proto files

The documentation is generated from this commit.

Commit:8a92b19
Author:Kevin Evans

feat: add `appBarTitle` in AndroidConfiguration proto

Commit:d5d8ebd
Author:Masayuki Ono
Committer:Masayuki Ono

Sound null safety

Commit:a87035f
Author:Julian Finkler

Protobuf models splitted and created models instead of using the protobuf models in the public api

Commit:156e1be
Author:Julian Finkler

Added more config options and created a result object instead of passing the barcode only

Commit:f4f3b21
Author:Julian Finkler

Platform communication with protobuf - Retrieve the number of available cameras with `BarcodeScanner.numberOfCameras` Flexible configuration: - Set the strings for the flash on/off and the cancel button - Restrict the detected barcode formats - Set which camera is used for scanning barcodes