`SamATM90E26_library` is not a library

[dmohns]

Currently, we have a library called SamATM90E26_library in our Library directory. However,

• It looks like the code is essentially coming from here: https://github.com/whatnick/ATM90E26_Arduino but not reference is provided
• This code is not used as a library, but instead users actually need to chance the code as part of the calibration process, see here

This can cause a lot of confusion amongst users and should be cleaned up.

This consists of two steps

1. First, move the code from Library folder into the main folder of the code to signal this custom code is part of the Firmware and subject to changes.
2. Refactor the code to re-use as much code from https://github.com/whatnick/ATM90E26_Arduino and move the customisations as part of the calibration into a more clear location.