Rename repository to better suit usage

[ES-Alexander]

This repo is useful for storing auto-generated information outside of just the vehicle parameters, as evidenced by the inclusion of MAVLink messages in #7.

I think we should rename the repo accordingly, to reduce future confusion.

There doesn't seem to be a consistent standard across the ArduPilot repos, but as a few potential options:

• Metadata (like Datasheets)
• VehicleMetadata or FirmwareMetadata (like CustomBuild)
• ardupilot_metadata (like ardupilot_wiki)
• auto-parsed-data (like node-mavlink-mappings)