Added modal for moving nodes

...va/it/inaf/ia2/vospace/ui/controller/NodesController.java

...c/main/java/it/inaf/ia2/vospace/ui/data/ListNodeData.java

...t/inaf/ia2/vospace/ui/service/MainNodesHtmlGenerator.java

...af/ia2/vospace/ui/service/MoveNodeModalHtmlGenerator.java

...va/it/inaf/ia2/vospace/ui/service/NodesHtmlGenerator.java

...t/inaf/ia2/vospace/ui/controller/NodesControllerTest.java

...t/inaf/ia2/vospace/ui/service/NodesHtmlGeneratorTest.java

vospace-ui-frontend/src/api/mock/data/nodes/folder1.json

vospace-ui-frontend/src/api/mock/data/nodes/folder2.json

vospace-ui-frontend/src/api/mock/data/nodes/root.json

vospace-ui-frontend/src/api/server/index.js

vospace-ui-frontend/src/components/Main.vue

vospace-ui-frontend/src/components/modal/MoveModal.vue

vospace-ui-frontend/src/main.js

vospace-ui-frontend/src/nodesReloader.js

vospace-ui-frontend/src/store.js