add possibility to backup all files from ESP

[tparvais]

Hello
I've plenty ESP in my house.
That would be great to add an option to download and zip all config+rules+extra files from each ESP found on the LAN
Thanks for your work

[Grovkillen]

I'm planning (once the new GUI is released) to shift my focus on getting the flasher too + net scanner a completely new approach. I will program it using Electron as engine and it will be a lot better in every aspect.