Re-compile protobuf definition of Control service. Implement required
messages on DropObjects RPC request and response messages. Implement
`DropObjects` method on Control service server of the node. Use
`StorageEngine.Delete` method as a deleted object handler on server.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Add NetmapSnapshot rpc to ControlService protobuf definition. Recompile
proto files. Add required method to server structure.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>