[Display Layout] User should be able to toggle grid lines (#3331)

* Display Layout grid toggle and dimensions

- Added toggle grid button;
- Added Layout 'size' properties;
- Very WIP!

* Display Layout grid toggle and dimensions

- Cleanup toolbar;

* new configuration layoutDimensions

* extract display layout grid to own vue component

* split toolbar structure into two structures

* allow toggling grid when editing display layout

* toggle grid icon show/hide state on click

* grid be shown on starting edit mode

* remove dimensions code for other display layout feature

* toggle icon after method completes

* change icon names

* update spec to include new action and separator

Co-authored-by: charlesh88 <charlesh88@gmail.com>
Co-authored-by: Deep Tailor <deep.j.tailor@nasa.gov>

src/plugins/displayLayout/pluginSpec.js

@@ -340,7 +340,8 @@ describe('the plugin', function () {
 
         it('provides controls including separators', () => {
             const displayLayoutToolbar = openmct.toolbars.get(selection);
-            expect(displayLayoutToolbar.length).toBe(9);
+
+            expect(displayLayoutToolbar.length).toBe(11);
         });
     });
 });