Discard IPv6 RA packets, which cause LwIP to overwrite the IPv4 DNS
servers, resulting in DNS queries hanging up because there are no
accessible servers.
Bug Fixes
* Improved hostname sanitization and buffer-size safeguards to prevent truncation and ensure DNS-compliant names.
* Hostname is now applied earlier during network setup and on reconnects (ESP32), improving connectivity and ensuring settings take effect.
* Solves the problem that ESP32 boards show as "ESP-xxxxxx" on the network, no matter if DNS name is defined or not
* (breaking fix) prevent hostnames with double ``WLED-`` prefix, like ``wled-WLED-kitchen``
New Features
* Added a length-aware hostname retrieval API with an mDNS-preference option and robust fallback behavior.
* Preserved legacy compatibility by providing a length-aware alias for legacy hostname preparation.
Open Ends
* mDNS name is not sanitized when registering the mDNS endpoint, to avoid breaking previous functionality
There is a version of the Olimex ESP32-POE board with an ESP32-WROVER
module which has a the ethernet clock connected to a different IO than
the version with an ESP32-WROOM module.
This commit adds a new runtime selectable variant for the WROVER version.
