Optimize LED strip configuration

[oxivanisher]

The first real world tests did show, that it is not easy to configure the LED strip order. Some ideas about that are:

• Group LEDs with the same order id and show the ID so that it is obvious which leds are in the same group.
• To make ordering simpler (especially on small screens), the strip configuration should be folding
• Each strip should have a button to let the strip flash. This should be done without the led controller, since it adds absolutely no benefit. Example: Send 8;255;0;0 to /d1ws2812/. Possible effects are documented here: https://github.com/oxivanisher/d1ws2812mqtt
• Reconnected LED strips should not get a new id
• LED strips should no longer get the order ID -1 at the beginning

[oxivanisher]

• The LED-Strip-UI is currently unusable if there are more strips than space on the screen, since any try to scroll the page moves strips around.
• Sorting strips is not working correctly (see video whatsapp chat).