Separate grid charge limit for battery charging in Predbat

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First: Thank you for all the work on this project! I really, really like it.

But...

I'm always frustrated when I want to limit battery charging power from the grid, but allow full-speed charging from solar (PV). Currently, Predbat only allows setting a global charge power limit, which applies to both grid and solar charging. This means the planning and predictions are not accurate for hybrid systems, where grid charging should be limited (e.g. due to grid constraints or tariffs), but solar charging should remain unrestricted.

I would like Predbat to support a separate configuration parameter (for example, grid_charge_limit) that sets the maximum charge power allowed from the grid. Predbat should use this limit when planning battery charging from the grid, while allowing higher charge rates from solar/PV. This would make the planning and forecasts much more accurate for users with hybrid systems.

I have tried using automations in Home Assistant to limit grid charging, and setting a lower global charge limit in Predbat. However, these approaches either restrict solar charging unnecessarily or do not allow Predbat to plan accurately, since it does not know about the grid-specific limit.

Many users have grid connections that cannot support full-speed battery charging, or have energy tariffs that make high-power grid charging undesirable. At the same time, they want to maximize solar self-consumption by charging the battery at full speed from PV. A separate grid charge limit would allow for much better optimization and planning in these scenarios.