Add packaging options to RTEMS Deployment.

RTEMS Deployment currently supports TAR and RPM package types for toolchain and RTEMS BSP configuration distributions. However, users of Debian-based Linux distributions and FreeBSD must currently use TAR packages, which cannot track dependencies, upgrades, or clean removals like a real package manager. This project will provide native packaging support for Debian (.deb) and FreeBSD (pkg) package types within RTEMS Deployment. A packaging abstraction will be implemented in Python and will be shared between both packaging backends by refactoring the existing RPM backend. This will provide a clean integration with our current deployment model. This will provide RTEMS toolchain installation and management support for developers using Debian, Ubuntu, and FreeBSD distributions with their native package managers. It will also provide integration tests, documentation, and a tutorial for future contributors to easily integrate other package types into RTEMS Deployment.