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

tests/message_exchange_block_per_block.nu

@@ -79,17 +79,18 @@ try {
     print "Resuming execution\n"
 
     print "Node 1 starts searching for the providers with the file hash"
-    let providers = app get-providers --node $SWARM.1.ip_port $file_hash | get 0
+    let provider = app get-providers --node $SWARM.1.ip_port $file_hash | get 0
     print $"The providers are:"
-    print $providers
+    print $provider
 
     print "\nNode 1 asks node 0 to provide the list of blocks it has for the file"
-    let received_block_list = app get-blocks-info-from --node $SWARM.1.ip_port $providers $file_hash | from json
+    let received_block_list = app get-blocks-info-from --node $SWARM.1.ip_port $provider $file_hash | get block_hashes
     print $"The blocks node 0 has are:"
     print $received_block_list
 
-    print "\nComparing to the actual block list"
+    print "\nComparing to the actual block list:"
     assert equal ($block_hashes |sort) ($received_block_list |sort)
+    print "Passed ! Block lists are the same"
 
     print "Creating the directory to receive the files"
     mkdir $output_dir
@@ -98,7 +99,7 @@ try {
     for $i in 0..<($received_block_list | length) {
         let $hash = $received_block_list | get $i
         print $"Getting block ($hash)"
-        app get-block-from --node $SWARM.1.ip_port ($providers | get $i) $file_hash ($hash) | get 1 | save $"($output_dir)/($hash)"
+        app get-block-from --node $SWARM.1.ip_port $provider $file_hash ($hash) | save $"($output_dir)/($hash)"
     }
     print "Finished getting all the blocks\n"