* Check for the "qrcodegen" subfolder in addition to "qrcodegencpp".
* Properly set an include flag as a library header is included with no
directory name.
Disabled by default until upstream will merge proposed PR.
Can be enabled by forwarding `-DDESKTOP_APP_USE_PACKAGED_QRCODE:BOOL=ON`
cmake build option.
Signed-off-by: Vitaly Zaitsev <vitaly@easycoding.org>
