Resolve pip v conda in tests

[deirdre-k]

Conda has been a helpful tool for managing dependencies in test environments, especially given its ability to specify python versions. However, it has become a burden, specifically relating to: 1) Issues with OpenMind downtimes, conda breaking often 2) Running pip install way too often during testing, slowing down process and introducing bugs such as "installing UNKNOWN package"

Goal:

• Remove conda from travis and jenkins tests, replace with venv or similar
• Identify workarounds for python version specification where needed

[deirdre-k]

Waiting for switch to python 3.11 (#101 and #824)

[deirdre-k]

See venv docs