Save configurations parameters to SPIFFS

[chunglam2525]

Save ESP32 memory by putting configuration parameter in ESP32 on-board flash chip
Parameters included:

• HTML Element
• Pin Number
• Constant Sensor value
• ???CSS/Favicon???

Benefits:

• Create easy to read code (Long HTML element)
• Save precious memory of ESP32
• Configuration can be saved on-board (i.e. Remember Last Connected SSID)

Additionally, modern web browsers accept compressed files as a response, compressing the HTML text file (.gz) could create more space on SPIFFS.

[hamishcunningham]

Looks good, thanks. How might the library code that you have from Ex07 integrate with storing HTML elements on file? I think perhaps it makes sense for stuff like CSS and favicons, but not so much for page templates? Definitely worth looking into though, and collaborating with #8 and others