Handle the limitations for 1 packet per signature

[spalmer25]

From #50 (comment)

On one side, an index parameter is required for the SIGN instruction:

• 0x01: to indicate that the packet does not contain all the data and that other packets will be needed to get all the data.
• 0x81: to indicate that no other packet will be needed to obtain all the data.

On the other side, a condition tells that requests to sign data in more than one packet will be refused. Probably because of the parsing of consensus operations/blocks.

These two information are conflicting

TODO

Please create an issue regarding the limitations for 1 packet per block. We can investigate later if this limitation would restrict the baking once we add more features (like adaptive issuance, slashing) in single signature.
Add all the relevant information in the issue details.

• Fix the conflicting information by:

  • Either change the parsing of consensus operations/blocks and allow multiple packets.
  • Or remove the dependency on 0x01/0x81 indexes and always sign a single packet.
  • Or other proposals

• Change the doc/apdu.md file