Error handling in jade-service-runner `serviceManager`

[bakon11]

Describe the bug When making request to jade-service-runner to start new service. Upon an error returns { "id": 1, "jsonrpc": "2.0", "result": { "error": { "code": 6969, "message": "unknown error" } } }

To Reproduce Steps to reproduce the behavior: Make call to start service that isn't installed { "jsonrpc": "2.0", "method": "startService", "params": ["multi-geth", "1.9.2", "kotti"], "id": 1 }