Update website documentation on compiling with the Arduino IDE

[hestiahacker]

https://www.airgradient.com/documentation/install-arduino-c3-mini/ should be updated to point to https://github.com/airgradienthq/arduino/blob/master/docs/howto-compile.md

This could be a 302 redirect, a link on the page that the user has to click or some other way. The important thing is that we don't have duplication of these instructions, as they will get out of sync.

For example, the website says to install v2.0.11 of the esp package in the board manager while the new instructions say to install v2.0.17).