Bluetooth and Jacdac don't play well together

[tballmsft]

Problem: The Bluetooth stack interrupts Single Wire Serial (SWS), so Jacdac doesn’t work when Bluetooth is active. This is currently addressed by disabling BLE (during application execution) in the pxt-jacdac extension.

Potential Solution: use GPIOTE in SWS in CODAL. That is, link GPIO line signal interrupt to Serial DMA to receive interrupt without intervention from the processor. This requires changes to lancaster-university/codal-core