Bonding dialog

See merge request !390

flash_rocket

See merge request !325

fix(ble): Turn off coded and 2M phys

Closes #172

See merge request !391

The 2M phy caused problems when turning on encryption. I'm also
disabling the coded phy as I don't know it it works and need to first
test it with a phone/central which has support.

Closes #172

See merge request !387

See merge request !388

Changes use of utime and ujson to time and json

Create weak links from MicroPython specific implementations of
modules to standard names. I.e. allow `import time` to import
utime module.

Adds an option to write a btsnoop compatible log file containing BLE
traffic. A new file is created after each boot if BLE is activated and
the `ble_log_enable` option is set in `card10.cfg`. The last 10 logs are
kept via log rotation.

BLE fixes 2020-2

See merge request !385

Mainly to ease development ATM

Not that it really matters much at the moment as we allow bondings at
any point in time, but this will hopefully change soon.

Upgrade to micropython v1.12

See merge request !384

See merge request !386