CB-6398 Support additional commands in blackberry10.json

Enables proxy 

blackberry10.json:
```json
{
    "blackberry-signer": {
        "-proxyhost": "localhost",
        "-proxyport": "8100"
    },
    "blackberry-debugtokenrequest": {
        "-proxyhost": "localhost",
        "-proxyport": "8100"
    }
}