(core) split sort and filter menu into its own button

Summary:
  - New sort and filter button has several states
     - Empty / unsaved / saved
     - offers small save/revert button when unsaved

  - Fix little issue with hanging tooltip when the refElem is disposed.
    - The problem was that if you hover the save (or revert) button
      and then click the button, it causes the button to disappear,
      but the tooltip was staying.

Test Plan: Updated all tests to match the new UI.

Reviewers: paulfitz

Reviewed By: paulfitz

Subscribers: dsagal, paulfitz

Differential Revision: https://phab.getgrist.com/D2795

app/client/components/ViewLayout.css

@@ -13,6 +13,7 @@
   font-size: var(--grist-small-font-size);
   font-weight: 500;
   text-transform: uppercase;
+  white-space: nowrap;
 }
 
 .viewsection_titletext {

app/client/components/ViewLayout.ts

@@ -200,7 +200,7 @@ export class ViewLayout extends DisposableWithEvents implements IDomComponent {
         ),
         dom.maybe<BaseView|null>(vs.viewInstance, (viewInstance: BaseView) => viewInstance.buildTitleControls()),
         dom('span.viewsection_buttons',
-          viewSectionMenu(this.docModel, vs, this.viewModel, this.gristDoc.isReadonly, this.gristDoc.app.useNewUI)
+          dom.create(viewSectionMenu, this.docModel, vs, this.viewModel, this.gristDoc.isReadonly)
         )
        )),
       dom.maybe(vs.activeFilterBar, () => dom.create(filterBar, vs)),