add install of networkx
fix aggregate to properly work with requisites
fix requisite checking to not be exponential
fix pkg aggregate to work when multiple states specify the same package
add some type hints to state.py to make the code easier to follow
fix case of pkg aggregate duplicate package.

Add slots to DependencyGraph

Pinned networkx to 3.1

Pinned networkx to latest version supported on python 3.8 to support running salt-ssh to systems with python 3.8

Fixed assignment of env in support helpers VirtualEnv

Restrict networkx version with contraints instead of in base

Fixed setting context retcode in some places where errors are returned.
Removed unnecessary pylint ignore comment.
Reverted importlib-metadata version bump.

Added networkx to versions report

Actually fixed VirtualEnv env assignment from kwargs