Add option to easily test sharding in local

### Is your feature request related to a problem?

Actually we need at least 11 nodes to test sharding (transaction not replicated on all nodes).
But this is really complex to run 11 nodes in a local env on 1 computer.

### Describe the solution you'd like

We should have something on the config that allow us to easily modify the storage constraints of the election.

### Additional context

I think for development a good constraint would be 3 storage nodes.
We should think about a way to test the geographical constraint too in local

Epic: #228

Start by reviewing issue #228 and the configuration and local setup used to run the node cluster. Determine where election storage constraints and geographical constraints are defined, then assess how development settings could support sharding with three storage nodes instead of 11. Done means a documented, maintainable approach for testing local sharding, including the geographical constraint question.

Written by the indexing model from the issue text.