feat: add number parser and validator

src/validation/validators/number.validator.ts

@@ -0,0 +1,18 @@
+import { TypeValidator } from './interfaces.validator';
+import { PropertyValidationError } from '../PropertyValidationError';
+
+export const number = Symbol('number');
+type NumberValidator = TypeValidator<number, typeof number>;
+
+export const NumberValidator: NumberValidator = {
+  type: number,
+  validateAndParse: function(value) {
+    const result = +value;
+
+    if (isNaN(result)) {
+      throw new PropertyValidationError({ value, type: this.type });
+    } else {
+      return result;
+    }
+  }
+};