New SNTP implementation

[victor-Lopez25]

Uses ST-LIB Scheduler instead of Lwip's scheduler.

Will use maximum one Scheduler task.

Example usage:

/* ... */
int main(void) {
    MainBoard::init();

    led_instance = &MainBoard::instance_of<led>();
    auto eth_instance = &MainBoard::instance_of<eth>();

    Scheduler::register_task(200'000, []{ led_instance->toggle(); });

    ST_LIB::SNTP::start("192.168.0.9");

    Scheduler::register_task(1'000'000, []{
        RTCData data = Global_RTC::get_rtc_timestamp();
        INFO("RTC: %u; %uyr %umon %uday %uh %umin %us",
            data.counter, data.year, data.month, data.day,
            data.hour, data.minute, data.second);
    });

    while (1) {
        eth_instance->update();
        Scheduler::update();
        Diagnostics::Hub::flush();
    }
}

Led is not needed but it is to show the board is doing work.

[github-actions]

ST-LIB Release Plan

• Current version: 6.3.1
• Pending changesets: 1
• Highest requested bump: minor
• Next version if merged now: 6.4.0

Pending changes

• minor Rework SNTP module in ST-LIB to use ST-LIB scheduler instead of Lwip one (.changesets/SNTP-impl.md)

[JavierRibaldelRio]

Except the requested changes, from my point of view everything looks fine.
Congratulations @victor-Lopez25

[JavierRibaldelRio]

The code works fine, was tested with me with using an ntp rust-builded server