Add backup and migrate option

[DarumaDocker]

No description provided.

[juntao]

Hello, I am a code review agent on flows.network. Here are my reviews of changed source code files in this PR.

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install.sh

Potential issues

:

1. The command 'gaianet' could not be found in your environment. Make sure to add '$bin_dir' to the PATH variable, and run it again. 2. There is no frpc binary available for $target architecture on this platform. You can use an alternative setup or try again with another architecture.

Summary of changes

1. Added options to backup and migrate configuration files.
2. The backup process is executed if the --backup option with a valid path is provided.
3. After the successful backup, the user can proceed by providing the backup file as an argument for the --migrate option during installation or upgrade.