Unable to connect in a proxy setup with path prefix

[Kleinjohann]

I'm running a crate cluster behind a proxy which forwards https://my.proxy:443/crate/ to internal.crate.hostname:4200. This requires me to prepend /crate/ to all paths which does not seem to be possible in crate-python. Am I overlooking something? If not, I would be willing to develop my current hacky fix into a fleshed-out solution and contribute it in a PR.