[EPIC] Update existing wallet models following the agreed architecture

[noeliaSD]

Description

According to the agreed architecture posted on the shared notion page, update the following identified wallet models following the pattern described.

Goals:

• Unifying criteria across all desktop teams while defining / exposing models to the QML layer.
• Have a unique source of truth in service layer with the most possible raw and generic data.
• QML layer will be decomposed into (Store --> Adaptor --> Views) and will be the only one responsible of transforming data according to the UI needs.
• Reduce NIM layer the most possible and use QML proxy models library instead.

This epic will be solved step by step, considering each model update as a different subtask. Here are the existing wallet models that should be part of the wallet section/module:

Exposition of context properties from NIM to QML

• src/app/modules/main/wallet_section

  • accounts/model.nim --> walletSectionAccounts --> it seems to have basic model data structure
  • activity/model.nim
  • all_tokens // Assets
    • flat_tokens_model.nim:
      • Sources property it's not a direct value but an operation that can be a potential performance issue
      • Description and WebsiteURL also to be considered
      • MarketDetails can be lazy loaded?? Can we share the same market details object in the flat_tokens_model???
    • sources_of_tokens_model.nim --> ok
    • token_by_symbol_model.nim --> Needs the grouping model
  • assets/grouped_account_assets_model.nim --> Ok --> It's a mirror of the UI need so probably a flat model whenn grouping model is done***
  • buy_sell_crypto/model.nim
  • networks
    • model.nim
    • combined_model.nim (probably candidate to be removed, flat model should be enough with some transformations on top for particular views)
  • saved_addresses/model.nim
    • the question is if it could be merged with accounts model (because probably addresses from both models can be e.g. target of send operation)
  • send
    • We should consider moving dirty state management from NIM side to UI and therefore substantially simplify interdependence of both sides, also the SendModel as a result
    • accounts_model.nim --> walletSectionSend --> accounts --> It seems a subset of walletSectionAccounts. Can it be removed?
    • suggested_route_model.nim
    • network_model.nim

• shared_modules

  • collectibles/controller.nim
  • collectible_details/controller.nim
  • keycard_popup/models/keycard_model.nim

• profile_section/wallet/accounts/model.nim --> it's the one for settings -- > Can it be removed?

• Collectibles model

  • Split into metadata / ownership models, to be joined QML-side
  • Account/Chain independent updates

Stores
Some stores are declared as Singletons:
status-desktop/ui/app/AppLayouts/Wallet/stores/RootStore.qml
status-desktop/ui/imports/shared/stores/RootStore.qml
It creates a dependency on context properties and breaks unit tests / storybook pages.

Subtasks:

• Update accounts base model and remove duplications in (send and settings "sections")
• In flat_tokens_model,Sources property it's not a direct value but an operation that can be a potential performance issue. Review Description and WebsiteURL

[noeliaSD]

It still need proper decomposition of subtasks.

[noeliaSD]

Some of the listed issues will be covered here:
#14618

Next steps:
#14715