Updated docs related to quantization

.gitignore

docs-src/docs/algo_quantization.md

docs-src/docs/design.md

docs-src/docs/imgs/training_quant_flow.png

docs-src/docs/imgs/use-flow.png

docs-src/docs/quantization.md

docs-src/docs/schedule.md

docs-src/docs/usage.md

docs/algo_quantization/index.html

docs/design/index.html

docs/imgs/baidu_rnn_pruning.png

docs/imgs/training_quant_flow.png

docs/imgs/use-flow.png

docs/index.html

docs/quantization/index.html

docs/schedule/index.html

docs/search/search_index.json

docs/sitemap.xml

docs/usage/index.html