load_dbnames() should use File::Spec or similar

[djzort]

Even though i literally never use windows, hardcoded forward slashes always bother me.

I also have a soft spot for caring about VMS which has its own fun and interesting syntax for filesystems (see https://metacpan.org/pod/File::Spec::VMS)

If someone is looking for something to do (i.e PR challenge) then reworking load_dbnames() to use File::Spec would be quite nice.