Using crates.io Categories to automatically populate crates

I've been thinking about this for a while and I think it would be very nice to have an automated way of populating the crates, instead of manually adding each of them.

## The AeroRust Website

We can integrate www.areweinspaceyet.org as part of the AeroRust website (e.g. like a menu item) and populate the crates using the crates.io Categories - [categories.toml] using the same design.

## Rust re-write
Instead of the Ruby app we can rewrite the server using Rust.
It will be easier to collect, parse and serve the website and easier to maintain as no Ruby knowledge will be required.

Tasks:
- We need the same information that the Ruby script currently generates
- Build the crates list using a list of categories to be included
- Whitelist & Blacklist for crates that are missing or wrongly categorized
- Decide if we should use a database dump (with https://crates.io/crates/db-dump) or crates.io. API (https://crates.io/crates/crates_io_api)

[You can see an example binary for collecting the crates' information by categories from crates.io here](https://github.com/elpiel/crates-categories)

## :heavy_check_mark: More categories on crates.io

We can ask in the crates.io repository how we can extend the categories that can be used for crates.
This will allow us the collect these crates from the registry and show them on www.areweinspaceyet.org

Currently, these categories exist, which are very insufficient for our needs:
- `[science]`
- `[science.categories.robotics]`
- `[simulation]`
- `[network-programming]`

There should be categories related to Aerospace and simulations related to aerospace, so it might be possible to create categories like:
- `[aerospace]`
- `[aerospace.categories.space-protocols]`
- `[aerospace.categories.drones]`
- `[aerospace.categories.unmanned-aerial-vehicles]`
- `[aerospace.categories.simulation]`
- `[aerospace.categories.protocols]`
- etc.

[categories.toml]: https://github.com/rust-lang/crates.io/blob/master/src/boot/categories.toml