Switch build system to Vite (#1444)

Switch Parcel to Vite

frontend/src/vite-env-override.d.ts

@@ -0,0 +1,17 @@
+// Allow `import` statements to work with SVG files in the eyes of the TypeScript compiler.
+// This prevents red underlines from showing and lets it know the types of imported variables are strings.
+// The actual import is performed by Webpack when building, as configured in the module rules in `webpack.config.ts`.
+declare module "*.svg" {
+	const content: string;
+	export default content;
+}
+
+declare module "*.png" {
+	const content: string;
+	export default content;
+}
+
+declare module "*.jpg" {
+	const content: string;
+	export default content;
+}