[feature]: Support using system fonts (#304)

* [feature]: Support using system fonts

Uses the **experimental** queryLocalFonts API, when prompted, to get the fonts and do CSS.
Resolves #270 and #288 (by proxy)

Caveats/notes:
- This is experimental, and is only supported by Chrome/Chromium/Edgeium (see https://caniuse.com/?search=querylocalfonts)
- As far as I can tell, the only way to dynamically change the font (shown in https://wicg.github.io/local-font-access/#example-style-with-local-fonts) was by DOM manipulation; css variables did not seem to work
- This shows **all** fonts, including their variants (bold/italic/etc); given that the style names could be localized, not sure of a way to parse this (on my system, for instance, I had 859 different combinations)
- I made fonts a separate top-level setting because it was easier to manipulate without causing as many rerenders; feel free to put that back

* add permission chec

* add electron magic to support custom font

* restrict content types

src/renderer/types.ts

@@ -203,3 +203,9 @@ export type SongUpdate = {
     /** This volume is in range 0-100 */
     volume?: number;
 };
+
+export enum FontType {
+    BUILT_IN = 'builtIn',
+    CUSTOM = 'custom',
+    SYSTEM = 'system',
+}