Publish operational state even in case of failure

Configured endpoints of jsonrpc:config could have a corresponding operational entry to indicate the state of the endpoint. This would be also be similar to the NETCONF mount point behavior.

When the configuration entry request has returned a status of 200 OK (HTTP status) the operational state provides the current status of the endpoint configuration. This can also provide a place to indicate error and reason when a mount configuration fails asynchronously. Currently this happen only when operation is successful so user need to check log to find out cause of failure