Explain <clientOnly> and other small docs improvements

[JuroUhlar]

Hi!

I tried using the SDK while writing https://dev.fingerprint.com/docs/usage-with-server-side-rendering-frameworks
a noticed a few things we could improve in the README here:

• We don’t mention that you need to wrap the component inside <clientOnly> and if you don’t, you get a 500 error that is not that helpful. We should mention this requirement in the Nuxt section.
• When you open the GH Pages version of the docs, the example Nuxt Application link does not work. It probably needs to be an absolute URL.
• The line import path from 'path'; in the Nuxt code block seems unnecessary, the path is not actually used for anything.