update: add new route to get service with slug

src/modules/danak-services/DTO/get-service-by-slug-param.dto.ts

@@ -0,0 +1,11 @@
+import { ApiProperty } from "@nestjs/swagger";
+import { IsNotEmpty, IsString, Length } from "class-validator";
+
+import { ServiceMessage } from "../../../common/enums/message.enum";
+export class GetServiceBySlugParamDto {
+  @IsNotEmpty({ message: ServiceMessage.SLUG_REQUIRED })
+  @IsString({ message: ServiceMessage.SLUG_STRING })
+  @Length(3, 150, { message: ServiceMessage.SLUG_LENGTH })
+  @ApiProperty({ description: "slug of the service", example: "service-slug" })
+  slug: string;
+}