Custom SS58 prefix

In the discussion https://forum.duniter.org/t/datapod-specifique-a-un-reseau-ou-agnostique/12198, there is the question if a datapod should be specific to a network. Since index request includes address as a string and data primary key is an address including a ss58 prefix, there should be a check on this prefix or we should remove it because irrelevant here. This issue should be fixed before use in production.