Add values to config.js

[NathanJesudason]

Describe the feature you'd like
Some values that are hard-coded, like offshoot clean time, wifi name and wifi password, bubble purge timings, hyperflush timings, should be stored in config.js so that we can just edit the config file to change those values instead of reuploading.

Acceptance Criteria
AC: Compile list of hard-coded values that should be stored into config.js, have those values read from SD card, document what, if anything, changes with sleep mode.