Node migration instructions documentation

1. Migrate with configurations and revenue from the old node
Execute the btfs repo command on the old node to retrieve node files and the configuration path
Copy the files and configuration directories from the old node to the customized path of the new node
Set the value of the new node's environment variable BTFS_PATH to the copied path
Start btfs daemon on the new node

2. Migrate without stats and revenue from the old node
Set the value of the BTFS_PATH environment variable of the new node to the updated node file and the configuration path (do not use the same repo path from the existing BTFS nodes)
Run btfs init -p -i on the new node
Start btfs daemon on the new node