Remove all those unnecessaries and optimize a lot

More details are here: CHANGELOG

A little optimize

• optimize code line number width
• fixed nav menu active background style
• upgrade tag cloud, see: https://github.com/D0n9X1n/hexo-tag-cloud
• update 404 default page styles
• add icp beian config entry: #57

full speed static resource loading

see changelog