[Portal] Docs: Winston/cnct 2314 consolidate documentation for in app wallets and ecosystem (#5443)

https://linear.app/thirdweb/issue/CNCT-2314/consolidate-documentation-for-in-app-wallets-and-ecosystem

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## PR-Codex overview
This PR focuses on restructuring and updating the documentation and components related to `thirdweb` wallets, including `In-App`, `Ecosystem`, and `External Wallets`. It includes deletions of outdated files and additions of new guides and features.

### Detailed summary
- Deleted multiple outdated `.mdx` files related to `In-App Wallet` and `Ecosystem` documentation.
- Added new images and updated asset paths for wallet-related components.
- Introduced a new `AuthList` component to display various authentication methods.
- Updated wallet security documentation to reflect changes in architecture.
- Enhanced the sidebar for better navigation of wallet-related topics.
- Revised various guides to improve clarity on wallet integration and user management.
- Added detailed sections on wallet pregeneration and linking multiple identities.
- Updated the `sign-in methods` documentation with clearer instructions and links.

> The following files were skipped due to too many changes: `apps/portal/src/app/connect/sidebar.tsx`, `apps/portal/src/app/connect/wallet/faq/page.mdx`, `apps/portal/src/app/connect/wallet/user-management/get-user-profiles/page.mdx`, `apps/portal/redirects.mjs`, `apps/portal/src/app/connect/wallet/security/assets/ecosystem-scoped.svg`

> ✨ Ask PR-Codex anything about this PR by commenting with `/codex {your question}`

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Author: ElasticBottle