Additionally don't save a CloneURL field inside the project type.
If in future some git source doesn't provide a clone url we could just calculate
it from project.RepoPath or call the remote api to retrieve it.
* client: always parse the json error message field and return its contents
* Use ErrBadRequest and ErrNotFound in every handler and command
* Gateway: by default pass underlying service error (configstore, runservice) to
client keeping the status code and message. In future, if some errors must be
masked, we should change the specific parts that need special handling.
