feat: implement modals with vue router 4

This is an implementation of the modals with the new possibilities of vue router 3.

See: https://github.com/vuejs/vue-router/issues/703#issuecomment-865066913 for a better explanation
and the linked example implementation: https://github.com/vuejs/vue-router-next/blob/master/e2e/modal/index.ts

src/components/tasks/partials/singleTaskInList.vue

@@ -8,7 +8,7 @@
 		>
 		</span>
 		<router-link
-			:to="{ name: taskDetailRoute, params: { id: task.id } }"
+			:to="taskDetailRoute"
 			:class="{ 'done': task.done}"
 			class="tasktext">
 			<span>
@@ -126,10 +126,6 @@ export default {
 			type: Boolean,
 			default: false,
 		},
-		taskDetailRoute: {
-			type: String,
-			default: 'task.list.detail',
-		},
 		showList: {
 			type: Boolean,
 			default: false,
@@ -167,6 +163,13 @@ export default {
 				title: '',
 			} : this.$store.state.currentList
 		},
+		taskDetailRoute() {
+			return {
+				name: 'task.detail',
+				params: { id: this.task.id },
+				state: { backgroundView: this.$router.currentRoute.value.fullPath },
+			}
+		},
 	},
 	methods: {
 		async markAsDone(checked) {