Implement topology peer representation

[EclesioMeloJunior]

Description

The Grid Topology organizes a set of authorities in a matrix-like format where each row authority only talks with their column neighbors, and each column authority talks with their row neighbors.

This issue defines how a authority looks like in the grid. The topology peer info should contains:

• vector of peer ids (usually the validator might have more than one peer ID)
• validator index (the index of the validator in the set of current validators)\
• discovery id (the authority public ID used to identify the authority in the current session, also used by Authority Discovery mechanism)