fix: resolve error in Tasks app

This commit introduces Tasks support to the AccountManager by:

- Adding a `tasks_model.xml` file defining various data kinds for tasks such as title, location, description, dates, priority, status, etc.
- Referencing this `tasks_model.xml` in the `AndroidManifest.xml` within the EeloAccountAuthenticator service metadata. This allows the system to recognize the account as a source for Tasks.