Remove front.css

[johngodley]

This moves all the CSS from front.css into style.css. The block then operates as a normal block without any additional loading of CSS files.

The reason a front.css was created is to better seperate the grid styles in the editor from the ones on the front. These are necessarily different (the editor has a very different DOM to the rendered block), but were causing clashes.

To work around this I've tied all the editor grid CSS to wp-block-jetpack-layout-grid-editor instead of wp-block-jetpack-layout-grid.

This should mean it will now work with block-based themes.

Fixes #170

[johngodley]

@jasmussen can you see any problems with this approach?

The PR might seem quite chunky, but it's mostly updating visual unit test snapshots, and removing code.

It'll certainly need some good testing with actual examples, but the visual tests show no difference on the front end, and I can't see any differences in the editor.

[jasmussen]

No, I think this makes a lot of sense. And in a quick test of this PR it seemed to work well.

What kind of testing do we have available other than to ping friendly folks to ask for their help? It looks and seems solid, but it sounds like a big shift. Maybe it isn't?

[johngodley]

I think it looks worse than it is. If problems are going to surface it will be in the editor, not the front end, so it should be fairly safe in terms of not breaking a site.

[jasmussen]

Let's do it.

[mkaz]

Confirmed this fixed the issue with a block-based theme and layout grid not working on front-end. 👍