docs: update router and TEE documentation for clarity and completeness

- Revised the "Router Networks: Joining vs Running" section to clarify the roles of joining and running a router.
- Enhanced the configuration details for worker nodes and TEE nodes, including setup instructions and examples.
- Updated the overview of Trusted Execution Environments (TEEs) with detailed attestation processes and security considerations.
- Removed deprecated documentation files to streamline content and improve navigation.

Author: dpshade