REACH-29 Save workspace into client file system

In the Flood we can save home workspace and custom node workspaces as files. And later we can restore this workspaces from files.
Save: the Dynamo receives a message about saving, saves all workspaces as files and sends them back to the Flood.
Upload: the Dyname receives a file as byte array, saves them as a file, upload this file, sends all needed for restoring the workspace data to the Flood
do not make MessageHandler too big - delegate a part of responsibilities about uploading file to separate class