Export BOM matrix to XLS file

Implementation of the possibility that enables users to export the whole item structure to an XLS file. The exported file respects the information contained in the item structure, thus allowing different analyses by the user.

Allow to import process characteristics to the item

Since the creation of process characteristics and process activity characteristics is performed directly in the SE Process component, it has been made available, while configuring the item, the possibility to import existing process characteristics, thus making it easier to associate this information with the item data.