NOJIRA : added documentation link when metadata documentation url has a value

NOJIRA : added documentation link to a new window when metadata documentation URL has been completed (actually was not displayed anywhere). This is done with a non invasive small image (22x12px), right to the metadata label.

IMPORTANT : in this commit (& pull request), not default activated ; you must add ^DOCUMENTATIONLINK to bundle_element_display_format in app/conf/app.conf or app/conf/local/app.conf to see the result

bundle_element_display_format = <div class='bundleLabel'>^LABEL ^DOCUMENTATIONLINK ^ELEMENT</div>