(core) Add a button and a tooltip to Access Rules page item, in View-As mode.

Summary:
- When in View-As mode, clicking the Access Rules page now shows a tooltip
  with a link to return to normal mode and open the Access Rules page.
- A "revert" button is shown next to the item with the same behavior.
- Implemented hoverTooltip() with various options. (It will have other uses.)
- Simplify creation of links based on UrlState:
  - Allow merging with previous urlState using a function
  - Add a helper function to merge in aclAsUser parameter.
  - Add setHref() method to UrlState

Test Plan:
Added test cases:
  - for tooltips generally in test/projects
  - for updating UrlState using a callback
  - for Access Rules tooltip and button behavior

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D2749

app/client/ui/TopBar.ts

@@ -44,7 +44,6 @@ export function createTopBarDoc(owner: MultiHolder, appModel: AppModel, pageMode
           docNameSave: renameDoc,
           pageNameSave: getRenamePageFn(gristDoc),
           cancelRecoveryMode: getCancelRecoveryModeFn(gristDoc),
-          cancelUserOverride: getCancelUserOverrideFn(gristDoc),
           isPageNameReadOnly: (use) => use(gristDoc.isReadonly) || typeof use(gristDoc.activeViewId) !== 'number',
           isDocNameReadOnly: (use) => use(gristDoc.isReadonly) || use(pageModel.isFork),
           isFork: pageModel.isFork,
@@ -105,15 +104,6 @@ function getCancelRecoveryModeFn(gristDoc: GristDoc): () => Promise<void> {
   };
 }
 
-function getCancelUserOverrideFn(gristDoc: GristDoc): () => Promise<void> {
-  return async () => {
-    const url = new URL(window.location.href);
-    url.searchParams.delete('aclAsUser_');
-    url.searchParams.delete('aclAsUserId_');
-    window.location.assign(url.href);
-  };
-}
-
 function topBarUndoBtn(iconName: IconName, ...domArgs: DomElementArg[]): Element {
   return cssHoverCircle(
     cssTopBarUndoBtn(iconName),