Updated iis-vdir-create.json.
Updated iis-vdir-create.json.

- Updated helper function names with approved verbs.
- Added an application name parameter.
- Virtual directories can be created under generic folders within applications, so splitting the path and testing if each part exists as an app or vdir limits the use cases for the template. Instead we allow the user to enter the name of the application and the path of the vdir separately.
- Updated help text for VirtualPath param.
- Added LastModifiedOn property.
- Updated LastModifiedBy property.

red-gate/Library,red-gate/Library