LDEV-5063 Do not allow empty weights in Learning Design authoringIf a weight is empty, it is filled with 0. If all weights are 0, theLearning Design is considered non-weighted.
LDEV-5058 Allow tool adding both on fresh build and afterwardsAs a column got removed from a LAMS core table, we need to make surethat all scenarios work well: an upgrade from previous version, a freshbuild and adding extra tools afterwards.