Implementing new scanner;

Closes #121 (closed). I've been researching different things and found out that the old scanner the app was using (https://github.com/dm77/barcodescanner) is no longer being updated or maintained. I've also noticed that it is using a lot of deprecated methods. I found this new scanner that I'm going to implement, to see how it works with the app. It uses same license as the current scanner. The scanner I'm going to implement is called ZXing Android Embedded (https://github.com/journeyapps/zxing-android-embedded). From my experience it seems to be more dynamic, reliable and faster than the current scanner.

TESTING: Launch the app and go to Guest Forms -> Guest Visit Check In (Local Database). Once at the scanner test different lifecycles of the fragment by pressing different buttons for example: back button, pressing home button, switch apps button, and by rotating the device. After you press one of those buttons or rotate the device, navigate back to the scanner. Make sure the scanner is scanning each time you revisit the scanner and check the log to make sure there are no errors occurring with the camera.

NOTE: Confirm Scan button was updated to log the current barcode when pressed if one has been scanned.

NOTE: See issue #118 (closed) to get the scanner working within the emulator

Here is an example screenshot of what the scanner will look like when working as intended