Removes the indoorairquality and airquality interfaces as the
plugin isn't the right place for these sort of voncersion.
Instead, this PR specifies the individual compounds that
for the base for air quality measurements and ties them down
to export raw data.
It's the client apps responsibility to translate those values
into Air Quality Index scales based on the location of user. I.e.
while Europe would use the CAQI (Common Air Quality Index), the
US would use the EPA AQI etc.
Michael Zanetti