Use data_directory_mode GUC for pgdata_permission service

[gleu]

This GUC is better because you don't need read and execute rights to the directory. It's available since v11, so we should use it for servers v11+, and use the old way for older servers.

[gleu]

BTW, I read about this GUC in https://thebuild.com/blog/all-your-gucs-in-a-row-datadirectorymode/