[Nonodo] Add support to voucher execution

[fabiooshiro]

Currently, nonodo doesn't support voucher execution. To add this feature to nonodo, we would need to:

• Add the concept of epochs to nonodo. Like the actual node, nonodo would have to close the epoch after some time based on the block timestamp from the base layer. Another option is adding a nonodo-specific API to close the epoch manually.
• Once the epoch finishes, nonodo must compute the proofs for all the outputs in the given epoch. To compute this proof, nonodo needs to keep track of the Merkle trees of outputs just like the server manager. Beware, this is a moving target because of the Output Unification cartesi/rollups-contracts#42 effort.
• Then, nonodo must compute the epoch claim based on the Merkle tree of outputs and submit this claim to the Authority contract.

This is a challenging task, so we should evaluate whether it is beneficial to implement this in nonodo. This would also make nonodo a much more complex project than it is now, making it harder to maintain.

Original issue reported by gligneul

[fabiooshiro]