proposal: replace `.json` with `/api` route

[gameroman]

Currently to get data for a package as JSON, you need to add .json to the end of a package name, for example https://replacements.fyi/is-number.json

I propose to change the route to /api/is-number, or /api?package=is-number, or something similar

The main reasons is when a package does not exist (for example https://replacements.fyi/nuxt.json), an html 404 page is returned instead of structured JSON

[ghostdevv]

The main reasons is when a package does not exist (for example replacements.fyi/nuxt.json), an html 404 page is returned instead of structured JSON

This could be fixed such that it returns json when requested via the accept header

[gameroman]

Also if there's ever a package will be added that ends with .json to the manifest, that could also cause problems