Upgrade to elm 19 and the latest elm-css

[stephenreddek]

Closes out #179

I'm not very familiar with elm-css so I'm not sure if I'm following best practices. The newest version is fundamentally very different from how it was being used in this project. I hope this is the right direction! I am completely willing to change how the css is being done here if I have implemented it incorrectly.

I thought the addition of elm-live would make it easier to get started for other contributors, but I can remove that if it is not in the right direction.

I noticed that the browser images that go around the screenshots are not working while testing. The styles being applied are the same and it works if you update the url to be at assets/ so I imagine it will work when deployed.

[prikhi]

Thanks for putting in the work! It might be a little while before I am able to review & test this.

[joelclermont]

@stephenreddek Totally agree with @prikhi. Thank you so much for the contribution! I'm a bit overbooked through the end of the month, but I will give this a careful review as soon as I can.