Improve performance with iOS scanning and service discovery

[adamfowleruk]

Currently when introspecting iOS devices without Herald installed there is a significant pause, especially in busy areas. This occurs due to the 200ms wait on Android when connecting to and introspecting iOS devices. This is done because 'deep backgrounded' iOS devices don't advertise their services, but are still accessible via GATT.

In the first instance, reduce, remove, or make async, or increase the max number of simulataneous connections for Android Herald API. (Async is likely the best approach here as discovery takes milliseconds).

In the second instance, look at making some performance gains in other ways:-

• Introduce a new flag called 'enhancedServiceIntrospection' disabled by default - this adds a feature flag for the current 'check iOS via GATT anyway' capability
• Check the advertisements for the Linux Foundation manufacturer data area, as well as the Herald service, to bypass the need to connect for discovery completely (Will work for both V1 and V2 protocol)
• Prioritise actions for all devices with LF manufacturer ID prior to introspecting any other devices