Convert ImpSWFDialog.src to ui

add ui file

Change-Id: I42af9b8969a07b4d738c1fd30fc8917f24f784c6
Reviewed-on: https://gerrit.libreoffice.org/6592
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>