release v.19.7

🗲FLASH WITH A BROWSER🗲

Features:

• ✨✨ new spectrum channel mode normalization function ✨✨
  • flattens spectrum by bringing up all of the RSSI readings to the peak value
  • resolves the 'valley problem' with channels hiding behind other channels of higher noise floor
  • to use it, wait until there are no active TX peaks across the whole spectrum and press FN2
    • to turn it off press FN2 again or use the reset blacklist UP/DOWN buttons (more reliable with UP/DOWN buttons - will be fixed next release)

Changes:

• #82 reverted AM AGC signal range changes done in v.19.6
  • this caused worsening of the reception for the current users and didn't improve the reception of the user this was targeted towards
  • kept the lowest gain table changed in v.19.6 so this is a partial revert, please let me know if this resolves all of the issues - if not I will do a complete revert of AM AGC to version that was present in v.19.5
• reverted last release changes so the spectrum channel mode load channel settings from EEPROM when PTT pressed
  • this makes more sense considering we might have channel specific configuration the spectrum doesn't know about i.e CTCSS code

Fixes:

• fix #81 fm radio 10s scan timeout, EEPROM frequency validation