Added dev_cdc example

[paulober]

It demonstrates how to use TinyUSB with a CDC
interface while using the Pico SDK stdio USB.

[lurch]

I know this PR is still in draft, so you may already be planning this, but a brief README.md explaining what this example does, and how to use it (e.g. does it appear on the host as two separate /dev/ttyACM devices?) would be really useful.

[paulober]

I know this PR is still in draft, so you may already be planning this, but a brief README.md explaining what this example does, and how to use it (e.g. does it appear on the host as two separate /dev/ttyACM devices?) would be really useful.

Thanks for the reminder. I added a section to the README.

[paulober]

Not sure if we would also expose the RESET interface?
I have some WIP on this but I doesn't get detected correctly at the moment.
WorkInProgressResetInterface.patch

[kilograham]

can you please add license to c/h source files:

/**
 * Copyright (c) 2023 Raspberry Pi (Trading) Ltd.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

You can add your name too.

[paulober]

can you please add license to c/h source files

Sure, added.