Allow external scripts to execute on folders if using %d parameter

Currently external scripts can only be run on files.

This patch allows calling them from project view context menu on folders under the following condition:
- %d parameter is used
- file related parameters (%s, %u, %f, %b or %n) are not used

When calling the script in any other way nothing changes - the directory of the current file will be passed as %d parameter.

REVIEW: 114582