Add LibreTiny support

[kuba2k2]

This PR adds support for LibreTiny to AsyncTCP.
Aside from several new #ifdef LIBRETINY conditionals, it was required to add support for non-IPv6 lwIP.
Context: ESP32Async/ESPAsyncWebServer#187

[Copilot]

Pull Request Overview

This PR adds support for LibreTiny to AsyncTCP by adding LIBRETINY-specific conditionals and handling for non-IPv6 lwIP configurations.

• Introduces LIBRETINY definitions and include adjustments in both header and source files.
• Conditions network initialization and address assignment logic based on lwIP IPv4/IPv6 availability.
• Modifies AsyncServer constructors to correctly handle IP address types under various configurations.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/AsyncTCP.h	Added LIBRETINY conditional definitions and FreeRTOS include macros
src/AsyncTCP.cpp	Wrapped logging, IP address initialization, and server begin logic with LIBRETINY and lwIP conditionals

Comments suppressed due to low confidence (1)

src/AsyncTCP.cpp:871

• [nitpick] Consider clarifying the differences between using 'addr.u_addr.ip4.addr' and 'addr.addr' in the IP assignment branches, as this could be confusing when maintaining the code across different lwIP configurations.

addr.u_addr.ip4.addr = ip;

[mathieucarbou]

Could you please also update the CI to add entries for Libretiny ?

[kuba2k2]

Could you please also update the CI to add entries for Libretiny ?

CI added and passing. For some reason, IDF checks are failing, but that also applies to previous PRs and commits; the errors are unrelated to the scope of this PR.

[mathieucarbou]

Thanks! I will check to see if other team members want or have time to look at the PR before merging and releasing.

[kuba2k2]

Ah, that should be better... The Copilot didn't detect such a silly mistake 😄

With this change, it is fully functional on real hardware.

[mathieucarbou]

@kuba2k2 : FYI: #64
I am disabling libretiny support for board generic-rtl8710bn-2mb-788k for now.
It does not compile anymore.