PYBv1.1 memory currently maxed out

[leviner]

Currently, we have ~150kb in the complete 'Sensors' folder. The PYB can fit ~90kb on its internal storage.

[seastate]

I've reduced the storage requirements slightly by removing two unneeded files from the AirQuality folder.

Also I created a new folder in MicrocontrollerSetup named Platforms, and moved the STM32 folder out of the Temperature and into Platforms.

This file is used only for firmware that doesn't have onewire.py precompiled. Most of the boards we're using use firmware that already has this driver, and since we are providing firmware we can add onewire to our builds.

The savings here are modest, and we will still need to omit some sensor folders that are not used on the pyboards (if not using sd cards as recommended) and possibly other microcontrollers. Many other modern boards have substantially more storage.

There is the possibility of precompiling other files from the sensor folders, e.g. the driver in GPS is large and might fit into firmware better than in flash. However that makes revisions difficult, they would require a reflash, and also hides the process from users which is undesirable.