Implement Display and TryFrom traits for DeviceType

Summary:
Implemented Display and TryFrom impls to generated DeviceType object in grpc_clients/identity/src/device.rs.
Being able to marshal the protobuf into a "more realized" object will likely be useful in the future for both devices and services.

Test Plan: Write unit tests located in grpc_clients/identity/src/device.rs for both Display and TryFrom.

Reviewers: varun

Reviewed By: varun

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D9384