Add an aerospace related crate

You can participate in #hacktoberfest by adding any crate to the areweinspaceyet.org list

# List of crates to be added

- [x] [sgp4](https://crates.io/crates/sgp4) (astrodynamics) #12
- [ ] [tello](https://crates.io/crates/tello) (sdk)
- [ ] [tletools](https://crates.io/crates/tletools) (parser, astrodynamics)
- [ ] [tle-parser](https://crates.io/crates/tle-parser) (parser, astrodynamics)
- [ ] [reed-solomon-erasure](https://crates.io/crates/reed-solomon-erasure) (error correction)
- [ ] [reed-solomon](https://crates.io/crates/reed-solomon) (error correction)
- [ ] [adafruit_gps](https://crates.io/crates/adafruit_gps)
- [ ] https://github.com/cubehub/doppler (doppler correction)
- [ ] https://github.com/cubehub/demod (demodulation)
- [ ] https://crates.io/crates/simconnect-sdk (SDK, simulations)
- [ ] https://github.com/mihai-dinculescu/msfs-2020-gps-link (SDK, simulation)

## Resource suggestions for crates
- [ ] Astronomy crates from https://github.com/rust-unofficial/awesome-rust#astronomy
- [ ] Industrial automation from https://github.com/rust-unofficial/awesome-rust#industrial-automation
- [ ] Simulation from https://github.com/rust-unofficial/awesome-rust#simulation

The configuration file for the categories and crates found on the website can be found in [scraper/config.toml].
To add a crate to the catalogue, you should know that there are 2 types of categories - crates.io categories and our own custom categories:

- Our custom categories - these are the categories that don't have an analogue category in crates.io. You can find those in the [scraper/config.toml] configuration file which do not include the `canonical_slug` key (which is the crates.io category slug).
- [crates.io categories found here] - those categories have the `canonical_slug` key found in the [scraper/config.toml] configuration file. For example https://crates.io/categories/aerospace::protocols has `canonical_slug = "aerospace::protocols"`

## How to contribute

- The category in which the crate should be placed must be part of the categories found in [scraper/config.toml] configuration.
- If the category is not present in the configuration file [scraper/config.toml], you can propose this category be added.
- If the crate should be added to one of the categories from [crates.io categories found here] you should open a PR in the crate's repo itself to include the given category in the [Cargo.toml categories](https://doc.rust-lang.org/cargo/reference/manifest.html#the-categories-field) section.

## Do you have other suggestions? Feel free to add any crate related to the aerospace Rust ecosystem for #Hacktoberfest

[scraper/config.toml]: https://github.com/AeroRust/AeroRust.github.io/blob/main/scraper/config.toml
[crates.io categories found here]: https://crates.io/categories