Write `get-file` and commands to get the list of blocks from another node

Description

This closes #1 (closed) by providing an API that allows to get a file with just its hash

Detailed list of changes

• add get_file, get_blocks_info_from and other things related to managing the filesystem
• add new commands to nu API
• remove DragoonBehaviour as it was not useful
• add two new tests for get_file and change the already existing test to use the new API

Note

The get_file is still very rough, the error management needs to be handled better to take into a lot more cases of failure

src/dragoon_network.rs

@@ -848,15 +848,17 @@ where
                             }
                     },
                     Some(block_response) = block_receiver.recv() => {
-                        //TODO check the blocks, save them, potentially make the file
+                        //TODO check the blocks with the proof, save them
+                        //TODO break when we get to k blocks (enough to make the file)
                         todo!()
                     }
 
             }
-            //TODO add a break condition or change the loop to a while with a boolean check
         }
-        //TODO await the response and start requesting the blocks
-        //TODO when you can reconstruct the file
+        //TODO try to reconstruct the file with the first k received blocks
+        //TODO if it fails, keep requesting block info, try to check which matrix is invertible taking k-1 blocks already on disk and one more that isn't
+        //TODO if it fails, do the same with k-2, etc...
+        //TODO when a combination of the blocks that works is found, request the missing blocks
         //TODO return the path where the file was stored
         todo!()
     }