- replaces the old image-based sensor countdown (only for Libre)
- will now work for all CGM systems that report a sensor start date (or sensor age in the case of Libre)
- if no current/valid data is found, the view remains hidden
- currently showing for Libre 2 EU BLE (14.5 days), compatible Libre via external transmitter (14.5 days), Dexcom G5/G6/One (10.0 days) and LibreLinkUp follower (14.0 days)
- starts at 0% progress for 0d and finishes at 100% progress for maxAge as per above line
- To simply UI, sensor countdown options are removed completely
- All maxAge values are in Constants file for easy updating if ever needed