Support TTGO ESP32 OLED (G511) board + enhanced battery status display

[fredzo]

Hi Alf45tar,

First off thank you for your great work on PedalinoMini ! I'm working on a project based on a TTGO ESP32 OLED board (http://www.lilygo.cn/prod_view.aspx?TypeId=50062&Id=1152&FId=t3:50062:3) to replicate an AirTurn pedal (https://www.airturn.com/products/airturn-bt200s-2-controller) used to control the looper of my Lâg HyVibe guitar.

In case you're interested, this pull request adds support for TTGO ESP32 OLED board. I also reworked the battery display for a better detection of the charging status with LiPo batteries.

Best regards,

Frederic.