0.2.0 release

[nickjalbert]

This is the release PR for version 0.2.0 of AgentOS and the Python Component System (PCS).

Major Changes

• Allow a Component to be a managed module, as an alternative to the existing support for a Component being a managed class or class instance (#295)
• Integrate VirtualEnv management into Component (#296)
• Separation of AgentOS and PCS into different top-level modules. Most non-RL-specific functionality of the project can now be accessed by importing module pcs (#328)

Minor Changes

• Delete Component.Identifier and replace all uses of it with ComponentIdentifier (#290)
• Simplify ComponentIdentifier by making it a subtype of str (#290)
• Moved Component import and instantiation into get_object() (#293)
• Fix bugs in build_docs.py script (#294)
• Add isort as a part of code formatting (#302)
• VirtualEnv can be created from setup.py files (#306)
• Updates to values in RunCommandSpecKeys (#313)
• Better handling of sys.path during Component import (#313)
• Only activate a Component's virtual environment once with no deactivate (#325)
• Fixes for dev requirements installation on Mac M1 (#326)

Other Notes

• We initially called this the v0.1.1 release, but then decided that the changes were big enough to call this the v0.2.0 release. So, if you still find any references to v0.1.1, let us know (they should all point to this release now). The deprecated release PR for the deprecated v0.1.1 is here NOW DEPRECATED; see 0.2.0 release. Formerly was 0.1.1 release. #344.
• Previous official release (v0.1.0): 0.1.0 release #279