Revert "[Docs] Simplify `build.md` (#370)" (#586)

This reverts commit 4b5c2bda.

docs/en/build.md

 ## Build from source
 
+- make sure local gcc version no less than 9, which can be conformed by `gcc --version`.
 - install packages for compiling and running:
-
   ```shell
-  conda create -n lmdeploy python=3.10
-  conda activate lmdeploy
-
-  git clone https://github.com/InternLM/lmdeploy.git
-  cd lmdeploy
-
   pip install -r requirements.txt
-  conda install openmpi-mpicxx nccl rapidjson -c conda-forge
   ```
-
+- install [nccl](https://docs.nvidia.com/deeplearning/nccl/install-guide/index.html), set environment variables:
+  ```shell
+  export NCCL_ROOT_DIR=/path/to/nccl/build
+  export NCCL_LIBRARIES=/path/to/nccl/build/lib
+  ```
+- install rapidjson
+- install openmpi, installing from source is recommended.
+  ```shell
+  wget https://download.open-mpi.org/release/open-mpi/v4.1/openmpi-4.1.5.tar.gz
+  tar -xzf openmpi-*.tar.gz && cd openmpi-*
+  ./configure --with-cuda
+  make -j$(nproc)
+  make install
+  ```
 - build and install lmdeploy:
-
   ```shell
   mkdir build && cd build
   sh ../generate.sh

docs/zh_cn/build.md

 ### 源码安装
 
+- 确保物理机环境的 gcc 版本不低于 9，可以通过`gcc --version`确认。
 - 安装编译和运行依赖包：
-
   ```shell
-  conda create -n lmdeploy python=3.10
-  conda activate lmdeploy
-
-  git clone https://github.com/InternLM/lmdeploy.git
-  cd lmdeploy
-
   pip install -r requirements.txt
-  conda install openmpi-mpicxx nccl rapidjson -c conda-forge
   ```
-
+- 安装 [nccl](https://docs.nvidia.com/deeplearning/nccl/install-guide/index.html),设置环境变量
+  ```shell
+  export NCCL_ROOT_DIR=/path/to/nccl/build
+  export NCCL_LIBRARIES=/path/to/nccl/build/lib
+  ```
+- rapidjson 安装
+- openmpi 安装, 推荐从源码安装:
+  ```shell
+  wget https://download.open-mpi.org/release/open-mpi/v4.1/openmpi-4.1.5.tar.gz
+  tar -xzf openmpi-*.tar.gz && cd openmpi-*
+  ./configure --with-cuda
+  make -j$(nproc)
+  make install
+  ```
 - lmdeploy 编译安装:
-
   ```shell
   mkdir build && cd build
   sh ../generate.sh