support functions written in another language like python

i think the best way to do this would be to create a plugin for the build system (esbuild) that can import a python file. this imported python file would generate javascript in the bundle that is just a module that execs the python code and pipes stdout as the function response. additionally it can pass in some of the request data to stdin of the python code.

additionally this likely needs to include the python binary in the build somehow...
- could do this by just downloading and putting in dist as part of yarn build
- or could just assume the bin is in path and include it in the dockerfile