(core) Initial data tables page

Summary:
- Added a new special page for viewing raw data widgets:
  - Implemented in DataTables.ts
  - Accessible only via the special URL path `/p/data`
  - Future diffs should make this page prettier and easily accessible
  - Shows a list of user tables
  - Clicking on a table name shows its `rawViewSection` by setting `GristDoc.viewModel.activeSectionId`. Note that in this case `GristDoc.viewModel` is an empty record, so this is a bit of a hack, but it works well and causes no known issues.
- Added `ViewSectionRec.isRaw` to know if the record represents a raw data widget.
- Added various restrictions in the UI for raw data widgets:
  - 'Delete widget' is disabled in the 3-dot widget menu.
  - Prevent hiding columns:
    - "Hide column" in the column context menu is disabled
    - The "VISIBLE/HIDDEN COLUMNS" section of the right panel > Table > Widget is hidden
  - The toggle bar isn't configurable to ensure that users know when raw data is filtered:
    - The filter bar always shows if and only if some filters are present
    - "Toggle Filter Bar" is hidden in:
      - Right panel > Table > Sort & Filter
      - The sort/filter menu next to the three-dot menu for widgets.
  - Other restrictions in the right panel:
    - In the Column tab:
      - 'Use separate settings' is disabled
    - In the Table tab:
      - In the Widget subtab:
        - 'Change Widget' is hidden
      - In the Data subtab:
        - 'Edit Data Selection' is hidden
        - 'SELECT BY' is hidden

Test Plan: Tested manually. The behaviour of raw data widgets may still change and they aren't easily visible to users yet.

Reviewers: georgegevoian

Reviewed By: georgegevoian

Differential Revision: https://phab.getgrist.com/D3248

app/client/widgets/FieldBuilder.ts

@@ -348,11 +348,15 @@ export class FieldBuilder extends Disposable {
                              dom('div.fieldbuilder_settings_button',
                                  dom.testId('FieldBuilder_settings'),
                                  kd.text(() => this.field.useColOptions() ? 'Common' : 'Separate'), ' ▾',
-                                 menu(ctl => FieldSettingsMenu(this.field.useColOptions(), {
-                                   useSeparate: () => this.fieldSettingsUseSeparate(),
-                                   saveAsCommon: () => this.fieldSettingsSaveAsCommon(),
-                                   revertToCommon: () => this.fieldSettingsRevertToCommon()
-                                 }))
+                                 menu(() => FieldSettingsMenu(
+                                   this.field.useColOptions(),
+                                   this.field.viewSection().isRaw(),
+                                   {
+                                     useSeparate: () => this.fieldSettingsUseSeparate(),
+                                     saveAsCommon: () => this.fieldSettingsSaveAsCommon(),
+                                     revertToCommon: () => this.fieldSettingsRevertToCommon(),
+                                   },
+                                 )),
                                 ),
                              'Field in ',
                              kd.text(() => this.origColumn.viewFields().all().length),