Develop in docker containers with vscode

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now we can develop in docker containers with vscode. the config file is in the branch named devcontainer-support.

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@huan Does the branch need to be merged into main branch?

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If we do not merge it, it is inconvenient for the developer to start the docker dev environment, because he should start from the branch containing the .devcontainer directory. But this directory is not necessary for other developers.

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One way to solve this contradiction is to clone the devcontainer-support branch and reset the branch and add a .gitignore file under the .devcontainer directory.