MWM features overlap to nearby regions

[pastk]

E.g. complex forest and river polygons go far beyond downloaded mwm border:

Basically the same feature is duplicated in full in several MWMs if it intersects them even a bit. And if both bordering MWMs are downloaded then those duplicated features are rendered twice.

Besides optimization aspect, if we'd want to continue with #569 or #6357 it could lead to ugly rendering when a "prolonged" country feature is rendered together with a simplified World version:

[pastk]

It should be possible to cut off the unwanted parts during the generation, but there could be some issues, e.g. if we cut a forest or park feature into two, then those "halfs" will have their own icons, which might look not nice. If a building is cut in half then it'll be visual also (as we draw a darker building outline) and it'll be possible to select both parts independently. Maybe a plain bbox size filter (e.g. cut only bigger features) will help to minimize those issues.

[pastk]

Some almost 1Mb size lakes duplicated in several mwms: https://github.com/organicmaps/organicmaps/issues/7450#issuecomment-2171580524

[pastk]

And another example of big areal polygons duplicated / overlapped between mwms is Dnieper river.

[pastk]

A similar duplication happens with coastlines - they're divided into very big square blocks. And each mwm which touches the block even slightly has to include its full version.