Update link scheme

[andreterron]

Looks like our blog links currently look like:

blog.val.town/blog/:slug

But from looking into our posts on hacker news, it used to be blog.val.town/:slug, we should remove the /blog/ to not break old links. And to avoid having "blog" in two places in the URL.

Report on Discord:
https://discord.com/channels/1020432421243592714/1190046447064842261/1190046447064842261

It would be awesome to redirect /blog/:slug to /:slug, just in case we shared links with the new scheme.