BISERVER-9706 - Issues with exported file names when exporting a data source created by the data source wizard

BISERVER-10078 - Metadata model is exported as an xml file instead of xmi
corrected exported files naming
Merge pull request #395 from aliakseihaidukou/BISERVER-9706-legacy

BISERVER-9706 - Issues with exported file names when exporting a data so...