BVApp: Update license to GPVv2+
See https://github.com/Berlin-Vegan/berlin-vegan-guide/commit/4e8ea5c3580d0bce630a0432fb714e149852857e,
this was agreed with every contributor on the mailing list.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
See https://github.com/Berlin-Vegan/berlin-vegan-guide/commit/4e8ea5c3580d0bce630a0432fb714e149852857e,
this was agreed with every contributor on the mailing list.