Possibility to change some of the SDKCONFIG settings via UI

[anabolyc]

Hey folks.

I was working on the web-installer for the snapclient, originally intending to pull the latest code from the master, but later decided to link the snapclient as a submodule and keep all installer-related files and binaries outside of the main repo.

Anyway, the majority of the boards the web-installer currently supports are only different in device name and sometimes basic things like pinouts. Looking at the similar installer for the squeezelite-esp32, they have a single binary for every board (allowing OTA update, among other things), and settings are read on the fly from the NVS settings, with the possibility to read and update values from the self-hosted UI.

So, I'd propose to set up a basic code infrastructure to

• Prepare NVS partition with some basic settings, like name and pins
• Read settings from the NVS on startup
• Provide a self-hosted HTTP or WebSocket API to save those settings and reboot
• Update a self-hosted UI to manage settings

I know it is nothing new; it was discussed before. But I'd look for some guidance on how to implement it right, and I'll give it a try.

The next step (and the actual goal of mine) is to allow configuring Ethernet and DAC, moving forward to specific DAC settings, like DAC mode and built-in EQ on the PCM5122 and TAS5805M, which is the ultimate goal.