Replace offset shifting animations with palette cycling

[morganchristiansson]

Using pos values from GameDataLoader broke the offset shifting animations that started crolling in unrelated textures.

Existing animations also jump as the offset resets in the animation cycle.

Do what s25client does - animate water and lava by cycling palettes.

[Flamefire]

A bit hard to understand the comment as it only describes 1 vector, not which one nor the other one. maybe add a using PaletteAnimation = std::vector<PaletteAnimData> and name the variable vector<PaletteAnimation> tilesetAnimations or similar

Especially the above

    auto& animData = global::tilesetAnimData[tilesetIdx8];
...
    for(auto& anim : animData)

is confusingly named if anim is of type PaletteAnimData but animData is not.
You could also turn it around and renamed PaletteAnimData to PaletteAnimation and the vector of that is AnimData to match this code, but not sure if this is clearer.

Anyway such variable vs type naming mismatches are a clear indication of (mis)namings that need to be improved.