add config variable to disable zbar scanning

src/main/java/com/sparrowwallet/sparrow/io/Config.java

@@ -58,6 +58,7 @@ public class Config {
     private int enumerateHwPeriod = ENUMERATE_HW_PERIOD_SECS;
     private QRDensity qrDensity;
     private Boolean hdCapture;
+    private Boolean zbarScan;
     private String webcamDevice;
     private ServerType serverType;
     private Server publicElectrumServer;
@@ -404,6 +405,14 @@ public class Config {
         flush();
     }
 
+    public Boolean isZbarScan() {
+        return zbarScan == null || zbarScan;
+    }
+
+    public void setZbarScan(Boolean zbarScan) {
+        this.zbarScan = zbarScan;
+    }
+
     public String getWebcamDevice() {
         return webcamDevice;
     }