Faster updates for the Field Service app

We've overhauled how we develop the Field Service mobile app. You won't see much changed (apart from our snazzy new purple branding) but this will enable us to address feedback and build new features faster.

If you have a purple icon, you're on the new app. Please update when its convenient for you to do so. Users on older versions of the mobile app will no longer receive updates, so to ensure no one is left behind, we will prompt all users to update next week.

🎶 Purple house, purple hou-uuuse 🎶