Scripts: refactor paddle bash shell scripts.

[wanglei828]

Fix #10073

[luotao1]

@wanglei828

• Could you write some backgroud why we need to refactor paddle bash shell scripts in the comments, since other people don't know the backgroud?
• Could you write a simple command example in the comments, since other people don't know how to use this script?

@typhoonzero @Yancey1989
Could you help review this PR? If we update the scripts, we need to update the command on both TeamCity and documents, since we tell users to run following commands to build from sources now.

docker run -it -v $PWD:/paddle -e "WITH_GPU=OFF" -e "WITH_TESTING=OFF" paddlepaddle/paddle_manylinux_devel:cuda8.0_cudnn5 bash -x /paddle/paddle/scripts/docker/build.sh

[Yancey1989]

FROM @luotao1

Could you help review this PR? I

Sure.

Thanks for @wanglei828's PR, could you create an issue to descript the background about this PR?

[jacquesqiao]

It seems that the indentation is not right.

[wanglei828]

I fixed the indentation.

[wanglei828]

I have created a issue to describe my goal (#10073)

[wangkuiyi]

Thanks to @wanglei828 for these very carefully developed scripts.

I see duplicated code snippets in the two bash scripts in this PR. I'd suggest to merge them into one.

Also, it would be great to update the documents, to add comments, or to add an issue, anyway, to describe the motivation and usage of the added script.

Given that we currently have multiple scripts for building, it would be helpful to explain what existing scripts could be deleted once after this PR is merged.

[wanglei828]

@wangkuiyi @luotao1 I have updated the "README.md" file to describe how to use the new scripts, please help review. Thanks!

[wanglei828]

@wangkuiyi Duplicate functions have been merged into one.

[wangkuiyi]

Thanks to @wanglei828 for this PR. I followed the issue and have some suggestions over there: #10073 (comment)