add wifi support

[CWempe]

If this project would support wifi it would be possible to add many nice features that will be mentioned in additional issues.

I guess this would be the best way to integrate wifi. https://github.com/tzapu/WiFiManager

Additionally it would be nice to show the wifi status on the display and maybe add a wps button in the settings page.

[CWempe]

I started to integrate homie-esp8266. see https://github.com/CWempe/SuperLEDstrip/tree/homie

So it supports the following features:

• wifi #3
• mqtt #7 only device basics, nothing related to LEDs
• OTA-update #5

There may be unknown limitations or disadvantages with this release.

[CWempe]

implemented in 78a719ce6630ef17b05810464e2b892e0cef193f