add night mode selection with .yml file configurable

[decaywood]

if u set the nightMode value as true in .yml config file, the night mode js code will appear in footer.html file,otherwise it's just the same as the old version.

[decaywood]

imported the dependency of AmazeUI lib to operate cookie in a easy way，if u dun wanna add additional lib,please modify the js code at line 144 in footer.html

[Huxpro]

@decaywood Thanks! The night mode is nice.

But, the import of Amaze UI is definitely needless. It increase 57.3 kb gzipped only for a cookie operation!

There is a HTML5 local storage for that. U should have a try.

[decaywood]

@Huxpro dependency of AmazeUI has been removed

lacking of expired time may be the main reason why i give up the local storage : ) finally, cookie works as well.

[theoptimalpolicy]

Why was this pr abandoned? I can't figure out how to set the background to black (I don't really know anything about css)