Add theme browser page accessible from game options

Removed the themes buttons that were in the ThemeEditorModal and only
left a "Revert to Default" button along with a link to the ThemeBrowser
page.

Split off the buttons into reusable components since they are now used
in two pages.

Display the themes in big cards with a zoomable screenshot. Applying the
theme now shows a toast with an option to undo the action.

The snackbar now allows ReactNode instead of only strings.

- Add link with details on how to create a new theme in the game.
- Add link to the theme-sharing discord channel.
- Add icons to the theme & style buttons in GameOptions
- Add "Theme Editor" button to ThemeBrowser
- Add "Style Editor" button to ThemeBrowser
- Move Styles related files into Themes folder
- Includes a modal that shows a bigger version of the screenshot.
- Change Snackbar to allow for ReactNode as the message

src/ui/Router.ts

@@ -37,6 +37,7 @@ export enum Page {
   StaneksGift,
   Recovery,
   Achievements,
+  ThemeBrowser,
 }
 
 export interface ScriptEditorRouteOptions {
@@ -82,4 +83,5 @@ export interface IRouter {
   toLocation(location: Location): void;
   toStaneksGift(): void;
   toAchievements(): void;
+  toThemeBrowser(): void;
 }