Consistently rename _read_nodeinfo to _read_entity

Signed-off-by: martin f. krafft <madduck@madduck.net>
Debug output for config file search

Signed-off-by: martin f. krafft <madduck@madduck.net>
Improve error handling in yaml_fs

Signed-off-by: martin f. krafft <madduck@madduck.net>
Prepend file:// to node_uri in yaml_fs

Signed-off-by: martin f. krafft <madduck@madduck.net>