BSEC support

Adds basic Bosch BSEC support.

BSEC is a proprietary library from Bosch which uses the BME680 to calculate an estimation of an "Indoor Air Quality". It takes complete control of the BME680 and performs a measurement every 3 seconds. This consumes about 0.9 mA on the 1.8 V rail. A later iteration of this driver might also allow to change the interval to 300 seconds to save energy.

Two configuration options are introduced. One to enable the driver (as it is a binary blob) and one to enable the debug prints of the driver. If the library is active, calls to the BME680 API will stop using the sensor directly and return a subset of the data gathered by the BSEC library.

You can use this https://phyphox.org/ "experiment" to access the data:

In addition the pycardium BME680 API and the BLE Environmental Sensing Service have been extended.