Use ad- tailwind prefix

[jrowlingson]

Addresses #178

Yes - we should probably prefix the Tailwind classes we're using, perhaps with ad- so they don't conflict.

cc @samselikoff

[samselikoff]

@pzuraq @dfreeman I'm 👍 on this but understand why people might hate me for it 😄

I have a future in mind where this sort of thing is done at build-time, so we still get to use vanilla classes but they're prefixed when the addon is used by others. But for now I think this change makes us a better citizen.

In retrospect Tailwind may not have been the best choice for styling this addon for these sorts of issues (it's hard to contain, based on global utilities, etc.) but I still do think it has many strengths for a project like this, notably preventing css debt from growing over time.

Hopefully I (or someone else) can eventually add these build-time features to ember-cli-tailwind in the future.

[pzuraq]

I 👍 as well, the only thing that bothers me occasionally about Tailwind is it makes customizing addon-docs' CSS hard, but tbh that's a good thing because it makes me fix things upstream more often 😛

Let's move forward with this for now