Add distributions with dependencies to Build Repository

[theory]

Add distributions with external dependencies to the build repository designed in #44. Update the #45 CLI to resolve and install dependencies as designed in #40. Integrate the pattern into the crate started in #42 & #43 and the CLI started in #44.

Done when two PGXS extensions with package dependencies are in the registry and can be automatically build, installed and tested on:

• Debian/Ubuntu
• RHEL
• macOS
• FreeBSD (if Implement metadata-driven PGXS compilation on FreeBSD #47 complete)
• Windows (if Implement metadata-driven PGXS compilation on Windows #46 complete)