(core) Implement updated DocMenu UI: list/card mode and sort mode.

Summary:
- Add org-wide currentSort and currentView, saved as user preferences.
- Add per-workspace currentSort and currentView, backed by localStorage.
- Move localStorage-based observables to a separate file.
- Move hard-coded data about example docs to a separate file.
- Add UI for toggling sort and view mode.
- Removed unused features of buttonSelect to simplify it,
  and added support for light style of buttons.
- Added `parse` helper method to StringUnion, and use it in a few places where
  it simplifies code.
- Set `needRealOrg: true` in HomeDBManager.updateOrg() to fix saving prefs for
  mergedOrg.

Test Plan: WIP: Fixed some affected tests. New tests not yet written.

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D2587

app/gen-server/lib/HomeDBManager.ts

@@ -1216,6 +1216,7 @@ export class HomeDBManager extends EventEmitter {
       const orgQuery = this.org(scope, orgKey, {
         manager,
         markPermissions,
+        needRealOrg: true
       });
       const queryResult = await verifyIsPermitted(orgQuery);
       if (queryResult.status !== 200) {
@@ -3198,11 +3199,11 @@ export class HomeDBManager extends EventEmitter {
         const prefs = this._normalizeQueryResults(subValue, childOptions);
         for (const pref of prefs) {
           if (pref.orgId && pref.userId) {
-            value['userOrgPrefs'] = pref.prefs;
+            value.userOrgPrefs = pref.prefs;
           } else if (pref.orgId) {
-            value['orgPrefs'] = pref.prefs;
+            value.orgPrefs = pref.prefs;
           } else if (pref.userId) {
-            value['userPrefs'] = pref.prefs;
+            value.userPrefs = pref.prefs;
           }
         }
         continue;