Major optimisation to add [optional] C++ kernel, 3-4x speedup, misc ifxes

What's Changed

C++ kernel for fast optimisation - 3-4x planning speedup

When enabled, a fast C++ version of the predictor is used for planning.

Currently supports x86 and arm 32/64 including Mac, falls back to python when not supported.

  prediction_kernel_enable: true

• C++ optimized kernel, gives 3-4x speedup on planning by @springfall2008 in #4169

Minor fixes

• Gateway debug print outs by @springfall2008 in #4144
• Fix AttributeError: max_days_previous not initialized before first full plan run by @springfall2008 with @Copilot in #4150
• Fix validator issues by @springfall2008 in #4142

Optimiser fixes

• Sustain in-progress forced export across plan cycles (anti-flapping on flat peaks) by @tieskuh in #4118

Cloud conection fixes

• Sigenergy MQTT fixes, fix zero rate export by @springfall2008 in #4172
• GECloud: Fix to avoid turning on real time mode for EMS as its not supported by @springfall2008 in #4143

Full Changelog: v8.43.1...v8.44.0