Something OpenRocket does pretty well is to provide a wide range of available motors already on the software.
Maybe we could do something similar with .json files.

There are 2 options for us to accomplish this issue:

1. Save .json files with all the information we may find available on internet.
2. Download and save several .eng files in the repo so we can install it along with the rocketpy package itself.

There's already na open PR solving this kind of issue in the first rocketpy hackathon (2020)