Add SD scan configuration options

[lukeswitz]

Usage:

Create a file named config.txt in the root folder of your SD card. It is read on init and configures scan variables.

Configurable Variables:

bool dedupe - remove duplicate networks from scans
bool showHidden - use the scan showHidden parameter
bool dynamicScan - drift to channels with more networks
int timePerChan - time to scan each channel in milliseconds

Example config.txt file:

dedupe=true
showHidden=true
dynamicScan=false
timePerChan=150

[lukeswitz]

closing until have a computer

[AlexLynd]

shiettt looking forward to when this is available lol :pensive: