R&I Misc UI 4b (#2271)

* Styling for selects
- New cleaner styling approach;
- New cSelect and appearanceNone mixins;
- Converted selects in Notebook, plot-options-edit;

* List View fixes
- Ellipsizing now works;
- Better icon and text alignment;

* Remove updateDrilledIn function and calls

* Telemetry Table editing styles

- Headers now have hover effects;

* Change 'toggle'-style toolbar buttons to reflect current state, rather
than what will be the setting once clicked
- When frame is hidden, button displays the frame-hidden icon, and
tooltip says 'Frame hidden';

* Enable all sub-object views in Display Layout to use numeric inputs for
x, y, width and height

* Toolbar sanding and polishing
- Button order tweaked to place stack order near X, Y, etc. inputs;
- Improved spacing between items themselves and separators;

* Fix indentation

* Fix indentation part deux

src/plugins/displayLayout/components/DisplayLayout.vue

@@ -171,8 +171,6 @@
                 if (itemIndex !== undefined) {
                     this.attachSelectionListener(itemIndex);
                 }
-
-                this.updateDrilledIn();
             },
             attachSelectionListener(index) {
                 let path = `configuration.items[${index}].useGrid`;
@@ -208,15 +206,6 @@
                     this.mutate(`configuration.items[${index}]`, item);
                 }.bind(this));
             },
-            updateDrilledIn(drilledInItem) {
-                let identifier = drilledInItem && this.openmct.objects.makeKeyString(drilledInItem.identifier);
-                this.drilledIn = identifier;
-                this.layoutItems.forEach(item => {
-                    if (item.type === 'subobject-view') {
-                        item.drilledIn = this.openmct.objects.makeKeyString(item.identifier) === identifier;
-                    }
-                });
-            },
             bypassSelection($event) {
                 if (this.dragInProgress) {
                     if ($event) {