Parse Navigators from MainNavigator

#### What is this about?

This is to track the work around separating Navigators out of the single file MainNavigator. This would establish a pattern and reduce the file size and separate concerns into manageable Folders for navigation.

## Potential Folder Structure Solution:
- Nav
- App
- Main
- [MainNavigator.js](./MainNavigator.js)
- Wallet
- [WalletModalFlow.js](./Wallet/WalletModalFlow.js)
- [WalletTabStackFlow.js](./Wallet/WalletTabStackFlow.js)
- [WalletTabModalFlow.js](./Wallet/WalletTabModalFlow.js)
- Asset
- [AssetStackFlow.js](./Asset/AssetStackFlow.js)
- [AssetModalFlow.js](./Asset/AssetModalFlow.js)
- Transactions
- [TransactionsHome.js](./Transactions/TransactionsHome.js)
- Browser
- [BrowserFlow.js](./Browser/BrowserFlow.js)
- Snaps
- [SnapsSettingsStack.js](./Snaps/SnapsSettingsStack.js)
- Notifications
- [NotificationsOptInStack.js](./Notifications/NotificationsOptInStack.js)
- [NotificationsModeView.js](./Notifications/NotificationsModeView.js)
- Settings
- [SettingsFlow.js](./Settings/SettingsFlow.js)
- Home
- [HomeTabs.js](./Home/HomeTabs.js)
- Webview
- [Webview.js](./Webview/Webview.js)
- Send
- [SendView.js](./Send/SendView.js)
- [SendFlowView.js](./Send/SendFlowView.js)
- NFT
- [NftDetailsModeView.js](./Nft/NftDetailsModeView.js)
- [NftDetailsFullImageModeView.js](./Nft/NftDetailsFullImageModeView.js)
- Bookmark
- [AddBookmarkView.js](./Bookmark/AddBookmarkView.js)
- Offline
- [OfflineModeView.js](./Offline/OfflineModeView.js)
- Payment
- [PaymentRequestView.js](./Payment/PaymentRequestView.js)
- Swaps
- [Swaps.js](./Swaps/Swaps.js)
- Password
- [SetPasswordFlow.js](./Password/SetPasswordFlow.js)

### Scenario

_No response_

### Design

_No response_

### Technical Details

_No response_

### Threat Modeling Framework

_No response_

### Acceptance Criteria

_No response_

### Stakeholder review needed before the work gets merged

- [ ] Engineering (needed in most cases)
- [ ] Design
- [ ] Product
- [ ] QA (automation tests are required to pass before merging PRs but not all changes are covered by automation tests - please review if QA is needed beyond automation tests)
- [ ] Security
- [ ] Legal
- [ ] Marketing
- [ ] Management (please specify)
- [ ] Other (please specify)

### References

[Previous exploration](https://github.com/MetaMask/mobile-planning/issues/1966)