feat: implement account switcher component and state management

- Add AccountSwitcher component for managing user accounts with UI for switching, adding, and logging out.
- Create account state manager to handle snapshots of account-specific states for efficient switching.
- Introduce utility functions for account management, including ID generation and avatar color assignment.
- Implement Zustand store for account management, supporting addition, removal, and state retrieval of accounts.

locales/nl/common.json

@@ -34,6 +34,9 @@
     "dismiss": "Sluiten",
     "or": "of",
     "sign_in_sso": "Inloggen met SSO",
+    "add_account_title": "Account toevoegen",
+    "add_account_subtitle": "Inloggen met een ander account",
+    "cancel": "Annuleren",
     "website": "Website",
     "imprint": "Colofon",
     "privacy_policy": "Privacybeleid",
@@ -58,6 +61,11 @@
     "storage_free": "Vrij",
     "storage_total": "Totaal",
     "sign_out": "Afmelden",
+    "sign_out_of": "Uitloggen van {account}",
+    "sign_out_all": "Uitloggen van alle accounts",
+    "add_account": "Account toevoegen",
+    "set_as_default": "Als standaard instellen",
+    "switch_account": "Account wisselen",
     "contacts": "Contacten",
     "calendar": "Agenda",
     "settings": "Instellingen",