[Docs] Add Chip back to `AppLeftNav`, make `href` links relative
[Docs] Add Chip back to `AppLeftNav`, make `href` links relative

Chip had been left out in #4560, and the absolute links would break when refering to a specific release, e.g.
http://material-uo.com/v0.15.2/

hwo411/material-ui,ichiohta/material-ui,matthewoates/material-ui,verdan/material-ui,lawrence-yu/material-ui,pomerantsev/material-ui,manchesergit/material-ui,lawrence-yu/material-ui,ichiohta/material-ui,andrejunges/material-ui,ArcanisCz/material-ui,janmarsicek/material-ui,w01fgang/material-ui,janmarsicek/material-ui,pomerantsev/material-ui,janmarsicek/material-ui,w01fgang/material-ui,kasra-co/material-ui,pancho111203/material-ui,mmrtnz/material-ui,matthewoates/material-ui,kasra-co/material-ui,igorbt/material-ui,mtsandeep/material-ui,hai-cea/material-ui,frnk94/material-ui,hwo411/material-ui,pancho111203/material-ui,janmarsicek/material-ui,manchesergit/material-ui,mit-cml/iot-website-source,kittyjumbalaya/material-components-web,igorbt/material-ui,frnk94/material-ui,ArcanisCz/material-ui,andrejunges/material-ui,verdan/material-ui,mmrtnz/material-ui,owencm/material-ui,mtsandeep/material-ui,kittyjumbalaya/material-components-web,mit-cml/iot-website-source,owencm/material-ui,mit-cml/iot-website-source,hai-cea/material-ui