Removed free plan and added paid plans for Shopify

I have no idea how this will go but I will learn how the market reacts to a higher end price vs free (which was the case since I launched the app on Shopify).

I'm quite nervous about it and feel quite vulnerable. I plan to let this test run for a month and then report back.

The customers have a 7 day trial so it'll be interesting to see how many start a trial and stick with the product.