Carts: Get rid of animation hack

[appgurueu]

Fixes #2950; also fixes the visual aspect of #1927 - the player is now rotated:

• offset the entity by +0.5 if rotated; as a bonus, this will also fix the previous incorrectly offset selection box

[sfan5]

I just wanted to give this my approal 🤔

Unrelated some smooth animation would be nice in the future, poor Sam must have a headache after riding such a track:

[SmallJoker]

After the offset is added this will look definitely better than the current one. The patch is surprising simple.

@sfan5 The rotation (of the cart) is actually interpolated client-side. It's just rather fast. It can also be observed when punching a cart into the other direction due to the direction <---> yaw connection. https://github.com/minetest/minetest/blob/9fc018ded10225589d2559d24a5db739e891fb31/src/client/content_cao.cpp#L1133

[sfan5]

What's the status here?

[appgurueu]

What's the status here?

Not finished. I remember this not being as easy as applying the appropriate offset.