Add barcode-detector-api-polyfill dependency and update environment variable declarations in SvelteKit project

node_modules/@zxing/library/esm/customTypings.d.ts

@@ -0,0 +1,16 @@
+/**
+ * This file contains some types to make our
+ * lifes easier when copy and pasting Java code.
+ * With it we can keep int, float, etc., references
+ * in code to keep as close as possible as the Java version
+ * but without the need to sacrifice ourselves with boring
+ * and annoying things.
+ */
+export declare type byte = number;
+export declare type short = number;
+export declare type int = number;
+export declare type float = number;
+export declare type char = number;
+export declare type List<T> = Array<T>;
+export declare type Collection<T> = Array<T>;
+export declare type Deque<T> = Array<T>;