Create documentation on using the envi sensor

[andrewg23]

Documentation on how to set up and interact with the environmental sensor will be useful in helping others learn how to use the environmental sensor. This documentation will include instructions along with example code.

[andrewg23]

I have added images to the documentation showing how to plug in the sensor to the Nano.
I think this issue can be closed after the documentation is reviewed by others and it is agreed that it is complete.

[andrewg23]

After multiple times of allowing the sensor to collect data for at least an hour, I noticed that about 30min of burn in are required before the gas resistance values stabilize. I will continue to run tests like this to see if the burn in is necessary every single time gas readings are taken or if it's just something that needs to be done now that the sensor is still fairly new and unused.

[andrewg23]

I have uploaded multiple csv files containing data from various tests I have run to find the optimal burn in time for the sensor.
I will next plot the data from all these tests to find which burn in time is best.