(core) Adding font options to the style picker

Summary:
Redesigning color picker:
- Single color palette (no light/dark switch)
- Ability to remove color (new empty button)

New font options in the color picker.
Font options are available on:
- Default cell style
- Conditional rules styles
- Choice/ChoiceList editor and token field
- Filters for Choice/ChoiceList columns

Design document:
https://www.figma.com/file/bRTsb47VIOVBfJPj0qF3C9/Grist-Updates?node-id=415%3A8135

Test Plan: new and updated tests

Reviewers: georgegevoian, alexmojaki

Reviewed By: georgegevoian, alexmojaki

Subscribers: alexmojaki

Differential Revision: https://phab.getgrist.com/D3335

app/client/widgets/NewAbstractWidget.ts

@@ -42,10 +42,9 @@ export abstract class NewAbstractWidget extends Disposable {
 
   constructor(protected field: ViewFieldRec, opts: Options = {}) {
     super();
-    const {defaultTextColor = '#000000'} = opts;
-    this.defaultTextColor = defaultTextColor;
     this.options = field.widgetOptionsJson;
     this.valueFormatter = fromKo(field.formatter);
+    this.defaultTextColor = opts?.defaultTextColor || '#000000';
   }
 
   /**