Open source package and environment management

Environment abstractions are currently unimplemented.

Envs are required for resolving externs from imported classes and systems like PyTorch packages.

Packages should be described using the Package property type, instantiated in the same memory space as the imported modules in the factory.

Environments should also be able to be cleared from the current memory space.

Example env managers to abstract include: Conda/PIP/Rez

The issue names no files or tests; start by locating the unimplemented environment abstractions, the Package property type, and the factory that creates imported modules. Trace how externs are resolved and how the current memory space is represented. Done means packages can be instantiated there, environment managers can resolve the named package sources, and environments can be cleared.

Written by the indexing model from the issue text.