Add logging library

[cr1tbit]

I'm terrified by the available logging libraries in platformio. I'm seriously considering writing my own.

Requirements:

• COLORS
• Adding own backends (log to serial, flash, mqtt, display, etc.)
• Handling both Strings, StringHelpers and basic formatted strings.
• Many levels, customisable levels

I already wrote a simple logging framework based on https://github.com/rxi/log.c and It's relatively simple task.

For now I'm testing ArduinoLog on another firmware, but I'm not really happy with it. The project is dead, there are some interesting features in pull requests, but since we're stuck in platformio environment, I can't even include those. Sucks to suck.