refactor(errors): extend errors from Error and add/assign statusCode

this is in preparation for updating the routes/handleException method, to get rid of "any" (and improve in general)

src/errors/not_found_error.ts

@@ -1,8 +1,9 @@
-class NotFoundError {
-    message: string;
-
+class NotFoundError extends Error {
+    statusCode: number;
     constructor(message: string) {
-        this.message = message;
+        super(message);
+        this.name = "NotFoundError";
+        this.statusCode = 404;
     }
 }
 

src/errors/validation_error.ts

@@ -1,9 +1,11 @@
-class ValidationError {
-    message: string;
-
+class ValidationError extends Error {
+    statusCode: number;
     constructor(message: string) {
-        this.message = message;
+        super(message)
+        this.name = "ValidationError";
+        this.statusCode = 400;
     }
+
 }
 
 export default ValidationError;