All the validation must be done inside the configstore since it's the source of
truth.
The gateway could also do some validation to avoid bad requests to the
configstore when needed or when the logic resides outside the configstore (like
project setup or user registration)
RemoteRepositoryConfigType defines how a remote repository is configured and
managed. Currently only "remotesource" is supported.
In future other config types (like a fully manual config) could be supported.
In future we may support specifying a remote source for a project without a
linked account and thus use a user provided token (saved in the project) or
other ways to define a remote repo (like standard git repos over ssh).
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.
Simone Gotti