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/i18n/locales/en.json

@@ -87,6 +87,7 @@
       "templates": "Templates",
       "layout": "Layout",
       "colors": "Colors",
+      "font-sizes": "Font Sizes",
       "fonts": "Fonts",
       "actions": "Actions",
       "settings": "Settings",