Introduce argName

This release introduces a new function to help with code maintainability and refactoring.

argName will be exported from a separate file due to an additional dependency on Reflect.

Example usage:

import ArgumentContracts from 'argument-contracts';

const { argName } = require('argument-contracts/arg-name');
const someParameter = 'The greatest parameter on earth!';

ArgumentContracts.assertNumber(someParameter, argName({someParameter}));
// Will throw error: Expected someParameter to be a number. Value received: "The greatest parameter on earth!"