(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

static/ui-icons/UI/FontBold.svg

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg xmlns:svg="http://www.w3.org/2000/svg" xmlns="http://www.w3.org/2000/svg" width="16px" height="16px" viewBox="0 0 16 16" version="1.1">
+	<path d="m 3.1950988,1.8354199 h 5.6903818 c 0.7545952,0 1.4782724,0.2997567 2.0118534,0.8333375 0.533581,0.5335808 0.833337,1.2572582 0.833337,2.0118535 0,0.7545952 -0.299756,1.4782727 -0.833337,2.0118535 C 10.363753,7.2260451 9.6400758,7.5258018 8.8854806,7.5258018 H 5.0918927" id="path3414" style="fill:none;fill-opacity:1;fill-rule:evenodd;stroke:#030000;stroke-width:1.26452935;stroke-linecap:round;stroke-linejoin:round;stroke-opacity:1" />
+	<path d="m 5.0918927,7.5258018 h 5.2161833 c 0.880352,0 1.724653,0.3497182 2.347169,0.9722207 0.622502,0.6225152 0.97222,1.4668161 0.97222,2.3471685 v 0 c 0,0.880353 -0.349718,1.724654 -0.97222,2.347219 -0.622516,0.622402 -1.466817,0.97217 -2.347169,0.97217 H 3.1950988" id="path3416" style="fill:none;fill-opacity:1;fill-rule:evenodd;stroke:#030000;stroke-width:1.26452935;stroke-linecap:round;stroke-linejoin:round;stroke-opacity:1" />
+	<path d="M 5.0918927,1.8354199 V 14.16458" id="path3418" style="fill:none;fill-opacity:1;fill-rule:evenodd;stroke:#030000;stroke-width:1.26452935;stroke-linecap:round;stroke-linejoin:round;stroke-opacity:1" />
+</svg>