Remove Google cross-site dependancies

[nuke-web3]

https://docs.substrate.io/ calls out to fonts.googleapis.com - I would love to see this requirement removed from the site, and port in fonts we need directly. I think this should be a simple fix @imadarai :crossed_fingers:

This would only require talking to our hosted site, no other origins (that can track) are needed :pray:

https://github.com/substrate-developer-hub/substrate-docs/blob/5fc09648489d729213c597021b04ac9674935c24/gatsby-config.js#L169-L178

[nuke-web3]

With the new docs, now I only see:

cloudcdn-img.com
d33wubrfki0l68.cloudfront.net

Are these explicitly needed? Otherwise we are 100% internal links only (per uMatrix anyhow :grin: )