Add sudo_options & 'env' parameters to run_command

[cceyda]

• add the sudo_options parameter to some commands that were missing it (instance: start & stop, list_instances)

• add an env parameter for passing environment variables to Client.instance and Client.execute
  I have been using spython to start some services dynamically and often found myself wanting to pass some environment variables, adding an 'env' parameter like this was a cleaner solution for me.
  If this is problematic and there is another way to pass many environment variables cleanly let me know

[vsoch]

This looks great! Please see my suggestion to use environ instead of env across functions. Then the final tweaks that will make it good for merge:

• please update the CHANGELOG with detail to the addition
• bump the version in spython/version.py

[vsoch]

This looks good to me! Let me know when you are all finished and we can merge and release.

[vsoch]

Looks like linting is failing - I would check your black version against the CIs https://app.circleci.com/pipelines/github/singularityhub/singularity-cli/301/workflows/c5bb4bec-2faf-430f-9282-664ce0462716/jobs/1162/parallel-runs/0/steps/0-114

[cceyda]

Looks like a lot of files(47) need to reformatted to pass that test and there are differences between different checks, what should I do?
spython-ci / formatting uses -> black-19.10b0
ci/circleci: Singularity 3.2.1 - Python 3 uses -> black-20.8b1

[vsoch]

heyo! Sorry for the delay! I just updated master with pinning a black version (and making the lints) so you should be able to rebase and update the PR here. fb33495

[cceyda]

~ Done ~

[vsoch]

Thank you @cceyda ! https://pypi.org/project/spython/0.0.85/