Adding ES error cases to createError

[RC-Lee]

Follow up of #63

Gave createError its own module so we could add cases for ElasticSearch errors.
Updated the tests to reflect the changes as well.

To test: pnpm test

For this change, the ES error will be created into an http-error indirectly first, before being sent into createError again as a nested error with additional props.
Doing so this way, we get to keep the ES error statusCode, it won't be overwritten.
However, I have no way of changing the description name of the final error to whatever ES might have named the specific status code to. The names are based on the status code that createError receives.
For example, a 404 status code will always be created as a NotFoundError, as shown below

    const elasticError = new errors.ResponseError({
      body: { error: 'testing ElasticSearch Error' },
      statusCode: 404,
    });

    const testESError = createError(503, elasticError);
    console.log(testESError);

The log would be something like

 NotFoundError: ElasticSearch Error:ResponseError
        at ... {
      body: { error: 'testing ElasticSearch Error' }
    }

So, it might be up for discussion if we want to keep the ES error status codes, or if we have it so they can be overwritten.

[humphd]

module.exports = (...args) => {

[humphd]

Add comments please to indicate what each path is doing in this if.

[humphd]

module.exports.createError = require('./create-error');

NOTE: always name files in lower-case, since not all filesystems are case sensitive.

[humphd]

Rename this file to src/create-error.js

[RC-Lee]

Changed the file name, added comments, and changed the module.exports line.
I've also added a new test to show cases where a status code is not included as the first argument.
http-errors will set the status to 500 in such cases.

  test('errors created without a status code should return a status of 500', () => {
    expect(createError('testing').status).toBe(500);
  });