More user-friendly node-cli when working with multiple archis

[cladmi]

When working with a multi-archi experiment, you can't use node-cli without specifying a nodes list to work on (or to exclude).

When running --reset command, with an experiment with M3 and A8 nodes you get the following output:

HTTP error: 400
You couldn't launch reset command with A8 archi nodes.

When running --update firmware.elf command with m3 and wsn430 nodes:

HTTP error: 400
WSN430 nodes must be associated with an HEX firmware file format.

So either the server could choose for the user and run only the command on the compatible node, or an option could be added to restrict the command to only one archi.