[WIP]feat: Session persistence and restore #287

[bifenglin]

Signed-off-by: bifenglin [email protected]

What do these changes do?

change session.py dag.py operation.py and context.py to persistence and restore the data

Related issue number

#287

Fixes

[welcome[bot]]

Thanks for submitting your first pull request! You are awesome! 🤗 Please make sure you have signed the CLA, as this is a mandatory check before a PR being merged. Welcome to the GraphScope community! 🎉 You can meet the community on DingTalk or Slack.

[CLAassistant]

All committers have signed the CLA.