Update smoltcp to 0.12.0 and embassy-net to 0.5.0

[AnthonyGrondin]

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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.
• I have added necessary changes to user code to the Migration Guide.
• 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 📖

Description

This provides an update for smoltcp@0.11.0 -> smoltcp@0.12.0 and bumps embassy-net to 0.5.0 for the examples.
I've only updated the API surface and examples so it builds; perhaps new APIs introduced by smoltcp@0.12.0 would be worth an internal driver refactor for optimization.
Closes #2662

TODO:

• Find a solution for [embassy-net]: Mutability mismatch between embassy_net_driver::RxToken::consume() and smoltcp::phy::RxToken::consume() embassy-rs/embassy#3670
  

  esp-hal/esp-wifi/src/wifi/mod.rs

  Lines 2684 to 2690 in 9a6afcf

  	/// Consumes the RX token and applies the callback function to the received
  	/// data buffer.
  	///
  	/// TODO: https://github.com/embassy-rs/embassy/issues/3670
  	pub fn consume_token_immutable<R, F>(self, f: F) -> R
  	where
  	F: FnOnce(&[u8]) -> R,

• Fix example for wifi_dhcp_smoltcp_nal.rs
• Write migration guide
• Add CHANGELOG entries.

Testing

CI needs to pass, and runtime needs to be tested.

[bjoernQ]

Lets just get rid of wifi_dhcp_smoltcp_nal.rs - we plan to reorganize / rewrite examples and the example isn't that useful

[AnthonyGrondin]

I'm wondering if this needs a migration guide. The update for esp-wifi is completely transparent, and the examples only really changed to demonstrate how to use the new embassy-net@0.5.0 release. We don't hardly depend on embassy-net for esp-wifi.

[bjoernQ]

Thanks!