Add ability to customize font size

Added an ability to customize font sizes. This is set at a new section in the settings.
The controler for this sets a number of css variables which are used in css rules that
override tailwind's text-<size> to use the font size and line spacing contained in the
variable. The control itself is a simple logarithmic slider that controls a "scale
factor" by which all the text sizes in a resume are scaled by.

src/data/rightSections.js

@@ -6,6 +6,7 @@ import {
   MdInfo,
   MdSettings,
   MdStyle,
+  MdFormatSize,
 } from 'react-icons/md';
 
 export default [
@@ -25,6 +26,10 @@ export default [
     id: 'fonts',
     icon: MdFontDownload,
   },
+  {
+    id: 'font-sizes',
+    icon: MdFormatSize,
+  },
   {
     id: 'actions',
     icon: MdImportExport,