Add contribution aggrement

Add aggrement
Add link to contribution agreement
make jobstable sortable on name
vaadin version fixes
Added a schedule type property: a job should either be chained or scheduled (issue #3)
pom update for lodms
switched memory repository for virtuoso repository
layout updates
updated lodms: seperated lodms-web from lodms for easier compilation

included seperate plugin modules (see repo ods-lodms-plugins)
updated requirements