Clean up error messages returned to client

[jdknives]

Most of the services we currently run seem to return the unmodified errors that may occur to the user. This exposes details of the cluster and implementation details we may not necessarily want to share with the user. Even if we do, these errors are difficult to understand for the user and should be cleaned up. Instead of just returning the plain error message, we should log the plain error message for us to use in analysing the problem and then returned a more generic error to the user.