refactor(ui5-list, ui5-tree, ui5-list-item-group): extract drag-and-drop logic#11928

kgogov wants to merge 3 commits intomainSAP/ui5-webcomponents:mainfrom

refactor-list-tree-drag-and-dropSAP/ui5-webcomponents:refactor-list-tree-drag-and-dropCopy head branch name to clipboard