Spike - putting Jedi behind a language server

[brettcannon]

Look at https://github.com/palantir/python-language-server and https://github.com/pappasam/jedi-language-server as options. And if those don't work we could use https://github.com/openlawlibrary/pygls to help wire everything up.

[brettcannon]

We should also look at how hard it would be to detect syntax errors with parso at the same time, allowing us to potentially drop Pylint if that's all we decide we need for baseline error detection.