Frontend skin page template

[Remian103]

pull request about #16

implement skin page!

• url : /skins/{skin_id}
• this page shows skin information corresponding to the skin id.
• have three component
  • timeline graph about skin price
  • skin info (name, ... would be updated)
  • carousel for other skins for champion of the skin

    router structure changed

• route code moved from 'index.js' to 'App.js'
• url
  • '/home' : main page (implemented in 'src/pages/Home.js')
  • '/' : redirected to '/home'
  • '/skins/{skin_id}' : skin page (implemented in 'src/page/Skins.js')
  • others : route to 404 page