feat(Carta Giovani Nazionale): [#176958889] Implementation of the redux store/actions section for Merchants list load and storage

[CrisTofani]

This PR Depens on #2807

Short description

This PR adds the scaffolding implementation of the store and reducer for CGN merchants list

[Undermaken]

Suggested change

	list: pot.Pot<ReadonlyArray<any>, NetworkError>;
	merchants: pot.Pot<ReadonlyArray<any>, NetworkError>;

Could it be a more descriptive name?
tip: if this store section includes only merchants, it can be directly the merchants list
export type CgnMerchantsState = pot.Pot<ReadonlyArray<any>, NetworkError>;

[CrisTofani]

@Undermaken
I used merchants as the attribute name in the CgnState since this section should have inside the merchants list and the selected merchant to show it's detail avoiding a navigation parameter. This was how i figured out the store:

{
  ...globalState,
  cgn: {
    ..cgnState,
    merchants: {
      list: [],
      selectedMerchant: {}
    }
  }
}

what do you think?

[Undermaken]

Good for me if this section will store also other data

[Undermaken]

We should avoid to use any
I guess it is just a placeholder but if we forget to replace it we can use the action and the reducer with no warnings from compiler.

Could instead possibile to create and use a temporary type?
type CGNMerchant = unknown;