CLI AS7-1833 connection management for shutdown and reload operations

This is an attempt to handle connection issues after reload and shutdown operations.

Unfortunately, it's based directly only the remoting3 api.

The CLI now receives and handles connection close notifications.

* Operations

shutdown and reload operations are executed as any other operation. But when the connection close notification is received and the operation executed was 'shutdown' then the cli switches to the disconnected mode. In case of reload, it will try to re-connect when the next command/operation is entered.

* Commands

The commit adds shutdown and reload commands. These will use execute requests and wait until the connection is actually closed and then will return the control back to the client.