gpio: DummyPin + hub75_i8080 example

[liebman]

Thank you for your contribution!

We appreciate the time and effort you've put into this pull request.
To help us review it efficiently, please ensure you've gone through the following checklist:

Submission Checklist 📝

• I have updated existing examples or added new ones (if applicable).
• I have used cargo xtask fmt-packages command to ensure that all changed code is formatted correctly.
• My changes were added to the CHANGELOG.md in the proper section.
• My changes are in accordance to the esp-rs API guidelines

Extra:

• I have read the CONTRIBUTING.md guide and followed its instructions.

Pull Request Details 📖

DummyPin for when you don't want/have a real Pin.

Description

This PR adds DummyPin. Useful in cases where you have to supply a pin but it wont really be used, like esp_hal::lcd_cam::lcd::i8080::TxSixteenBits but you only want 14 bits. The included example does exactly this driving a HUB75 LED Matrx display using the lcd_cam peripheral.

Testing

Tested on esp32s3 with the new example.

[liebman]

The example does this:

[bjoernQ]

I can't test the example but the dummy pin is useful

[JurajSadel]

LGTM, I also don't have a way of testing the example, I will ask, if someone from the team could give it a try. Thanks!

[MabezDev]

Thanks for the PR! I like the dummy pin, but I think the example is probably not required. We won't be able to test it and it will likely bit rot over time. Could you remove it?

[MabezDev]

Thank you!