Port TensorFlow Lite Motion Kit project

[hathach]

This PR port Tiny Motion Trainer https://experiments.withgoogle.com/tiny-motion-trainer. Changes is quite a lots

• Update CMSIS from 5.4.0 to 5.7.0 to build with latest TensorFlowLite v2.4.0
• Enable dsp libmath to build with latest TensorFlowLite v2.4.0 (close adding in support for DSP functionality, #626)
• Implent BLEUuid to allow initialize Characteristic and Service following ArduinoBLE style
• Implement Server/Characteristic constructor

    BLECharacteristic(BLEUuid bleuuid, uint8_t properties);
    BLECharacteristic(BLEUuid bleuuid, uint8_t properties, int max_len, bool fixed_len = false);

• Add BLECharacteristic readFloat() and writeFloat()
• Add BLEUuid::toString()
• Fix add support for CMSIS arm_math math hardware accelerator on nRF52 chips #625

PR failed to build since it requires

• CMSIS 5.7.0 will trigger ci when tools is released with json index
• Support Arduino API Adafruit_LSM6DS#21 and add arduino API Adafruit_LIS3MDL#6