Matching python versions

Currently the executor components assume that a consistent Python3 version and environment is available across the submit side, the interchange, and the workers. This is difficult and most likely terrible to enforce from a user-experience standpoint.

One potential solution is to relax some of the constraints and checks on version matching.

Note: We need to confirm whether it is just pickled functions alone that don't port between python versions.

If the above is right, we can get away with only enforcing python versions at the manager level.