feat(services): add getBySlugBrand function in brand.service

Adds a new function `getBySlugBrand` in `brand.service.ts`. This function retrieves a brand by its slug, providing a more specific search option. It implements error logging for missing slug or brand not found scenarios, and successful retrieval of the brand.

Issue: #13
Signed-off-by: Mathis <yidhra@tuta.io>

src/services/brand.service.ts

@@ -78,10 +78,31 @@ async function getAllBrand(): Promise<Array<IDbBrand>| false> {
 	return brands;
 }
 
+/**
+ * Retrieves a brand by its slug.
+ *
+ * @param {string} brandSlug - The slug of the brand.
+ * @returns {Promise<IDbBrand|false>} - A promise that resolves to the retrieved brand object or false if the brand is not found.
+ */
+async function getBySlugBrand(brandSlug: string): Promise<IDbBrand | false> {
+	if (!brandSlug) {
+      logger.error("Brand slug is missing");
+      return false;
+  }
+	const brand = await MysqlService.Brand.getBySlug(DbHandler, brandSlug);
+  if (!brand) {
+    logger.error(`Brand not found (${brandSlug})`);
+    return false;
+  }
+  logger.info(`Retrieved brand by slug successfully (${brandSlug})`);
+  return brand;
+}
+
 const BrandService = {
 	create: createBrand,
 	update: updateBrand,
 	getAll: getAllBrand,
+	getBySlug: getBySlugBrand,
 }
 
 export default BrandService;