Enable building css so that you can run blacklight without sass

[jcoyne]

Fixes #3206

[jrochkind]

I'm trying to follow why it requires a new build.css css file, what made the previous top-level CSS file not pre-compilable/buildable?

Also does this require a new CI build, or since CSS isn't really super testable by CI not worth it, or other reason it's not required?

[jcoyne]

@jrochkind the build.css is needed so that we have an entrypoint to build from within the gem. In the past we've used application.scss within the host application as the entrypoint.

[jrochkind]

Thanks @jcoyne

You building on gem release, then?

I had missed that, I had imagined it was building on assets:precompile for the app. Did I have it wrong, you are choosing to build on gem release and bundle built css with released gem?

[jcoyne]

@jrochkind Yes, the idea here is that we ship precompiled CSS so that the user doesn't need to install Sass (unless they want to). This should make it easier for new adopters as they don't need to worry about any node dependencies.