Implement Token VP

[Acentelles]

As part of the Sudoku example, a token VP to give a reward is needed.

Outline of the tasks:

• Define the token type
• Figure out how to encode the data to value base
• Make the type of the value base unique
• Figure out how to spend a note and how to create a note
• In previous versions, we have sendvp and receivevp. We need to encode those into the app_data_dynamic

The spendvp is more important. For now, everyone can receive the notes. The spendvp needs to check signature #52

[Acentelles]

It's part of #5