Features/remove aspects

# Status: ready to merge

Responsible: Johan F
Reported: Johan F

Info: This removes the ImageAspect model, and simplify the aspect ratio logic with a constant.

Having ImageAspect as a model, means that cropping doesn’t work without seeding first and we only ever create 6 aspects, that’s not likely to be changed ever. Their is no reason not to have this hardcoded into image crops.

However their is a lot of reasons to actually remove aspects:
* Again it only holds 6 records! Maybe once we will add a new aspect or two, but that's still way to few for a whole table.
* It's a very complex query to fetch a image with crop and aspect, something we do A LOT.
* Having ImageAspect as a seperate model is logically more complex and makes it harder to update images, then just using enum.
* Enum is made for these cases, so it's a much better fit.
Actually, maybe i should remove that, it should properly not be a part of the image system gem. But yes on our platform, would 0 be "original" :)