fix translation upload

- set the encoding to utf-8 on the json part
- change all parts to appropriate type
- change endpoint back to correct endpoint
- Use `ResteasyClientBuilder` instead of `ClientBuilder`
  - I honestly have no idea the difference b/w the two
downgrade httpclient

 - resteasy-client uses v4.2.1, so we should too
 - their pom stupidly doesn’t pull in the dependency so we have to
declare it here
cleanup imports
remove self-endpoint