LPS 33680 asset links exporting

Hi Máté.

I separated the pull in various commits:

- The fix of the problem. For this,  I changed the links.xml content in order to export the weight, and the import process to read it.
- The integrated test created to test the import/export process.  In this part I needed to add a new finder
- The javadoc
- Autogenerated code

This is my first "complex"  pull ( not too much :D ), so if you detect any mistake, please let me know

Thanks