[Frontend] Converting tree items and labels to flex-box

open #431
In-progress fixing mobile;
Removed desktop and mobile-specific hide/show;

platform/commonUI/general/res/templates/tree-node.html

@@ -26,40 +26,18 @@
             ng-class="{selected: treeNode.isSelected()}"
             >
             <span
-                mct-device="desktop"
                 class='ui-symbol view-control flex-elem'
                 ng-class="{ 'has-children': model.composition !== undefined, expanded: toggle.isActive() }"
                 ng-click="toggle.toggle(); treeNode.trackExpansion()"
                 >
             </span>
-
             <mct-representation
-                mct-device="desktop"
+                class="l-flex-row flex-elem grows"
-                class="mobile-hide l-flex-row flex-elem grows"
                 key="'label'"
                 mct-object="domainObject"
                 ng-click="treeNode.select()"
                 >
             </mct-representation>
-            <mct-representation
-                mct-device="mobile"
-                class="desktop-hide"
-                key="'label'"
-                mct-object="domainObject"
-                ng-click="(model.composition === undefined) && treeNode.select();
-                          toggle.toggle();
-                          treeNode.trackExpansion();"
-                >
-            </mct-representation>
-
-            <span
-                mct-device="mobile"
-                class='ui-symbol view-control'
-                ng-model="ngModel"
-                ng-click="treeNode.select()"
-                >
-                }
-            </span>
         </span>
         <span
             class="tree-item-subtree"