Update App for Fitbit OS SDK V4.1 and Support for New Fitbit Device Versa 2

[princessleia1]

Currently dog-walker is built on Fitbit OS SDK V.3.1.0 and does not support the new Fitbit Device Versa 2.

TODO:

• Update code for Fitbit OS SDK V4.1.
• Update code for compatibility for Fitbit Device Versa 2.
• Update Build Targets in package.json.
• Test New Build on Ionic, Versa, Versa 2 Devices.