Add workspaces, admin

- removed main.rs (middleware is library)
- added small documentation for middleware (features of middleware)
- added configuration for server
- added configuration for auth server
- added documents for configuration
- added example for using `Config` and `AuthServer`
- added function to make `rustls::ServerConfig` (todo)
- reformatted Cargo.toml and added `include` part of `package` in
  Cargo.toml
- will be using tokio + rustls for connection in connection

Since there was no actual code running, no test was written.

- changed comments to doc comments
- removed `make_tls_config` function
- changed `rustls::ServerConfig` to `key_path` and `cert_path`
- removed `custom_debug_derive` dependency
- added `serde` dependency
- changed example in document

Export admin folder to CubbyAdmin