Test benefits of pandas parallelization libraries

[jtec]

Libraries such as

• https://github.com/jmcarpenter2/swifter
• https://modin.readthedocs.io/en/stable/getting_started/quickstart.html

promise big speedups to dataframe operations, so we'll want to test their potential to accelerate prx. https://modin.readthedocs.io/en/stable/getting_started/quickstart.html seems especially promising, as it looks like they try to completely emulate the pandas API.