feat: added sizeLimit option when creating new jobs. issue #1357

Created by: joshterrill

This is my first PR for this repo, I thought this issue would be a good one to get started on. This resolves issue #1357 and adds an optional parameter for sending through a sizeLimit parameter on opts when creating a job. If the data you're sending through is larger than the sizeLimit set, an exception is thrown.

A couple of notes:

1. I added a dependency called bytes which is a small dependency which allows a user to type a "human readable" sizeLimit such as 1b, 1mb, 1gb, etc. instead of having to convert everything to bytes themselves. I also added a utility function so that a user can either set the limit as a number in bytes, or the human readable format. If you don't want this other dependency there, let me know and I can make it so that it'll just take the number in bytes that a user types in.

2. I implemented a utility function that I saw on this stack overflow post that describes how to count the size of strings, which also include non-ascii characters. Just to be safe, and to support other character encodings, I use this method to calculate the size.