cherry pick deepmodeling#564: add more badges (deepmodeling#965)

* add more badges

* fix the document badge link

* remove conda badge as it doesn't work

README.md

@@ -1,7 +1,11 @@
 <span style="font-size:larger;">DeePMD-kit Manual</span>
 ========
 [![GitHub release](https://img.shields.io/github/release/deepmodeling/deepmd-kit.svg?maxAge=86400)](https://github.com/deepmodeling/deepmd-kit/releases)
-[![Documentation Status](https://readthedocs.org/projects/deepmd/badge/?version=latest)](https://deepmd.readthedocs.io/en/latest/?badge=latest)
+[![doi:10.1016/j.cpc.2018.03.016](https://img.shields.io/badge/DOI-10.1016%2Fj.cpc.2018.03.016-blue)](https://doi.org/10.1016/j.cpc.2020.107206)
+[![offline packages](https://img.shields.io/github/downloads/deepmodeling/deepmd-kit/total?label=offline%20packages)](https://github.com/deepmodeling/deepmd-kit/releases)
+[![pip install](https://img.shields.io/pypi/dm/deepmd-kit?label=pip%20install)](https://pypi.org/project/deepmd-kit)
+[![docker pull](https://img.shields.io/docker/pulls/deepmodeling/deepmd-kit)](https://hub.docker.com/r/deepmodeling/deepmd-kit)
+[![Documentation Status](https://readthedocs.org/projects/deepmd/badge/)](https://deepmd.readthedocs.io/)
 
 # Table of contents
 - [About DeePMD-kit](#about-deepmd-kit)