clippy ci

[Vrixyz]

• Fixes clippy warnings
• forbid warnings within CI

Addressed doubts

I'm not too sure what to do about this error:

warning: methods with the following characteristics: (`to_*` and `self` type is `Copy`) usually take `self` by value
  --> crates/parry3d/../../src/transformation/polygon_intersection.rs:48:21
   |
48 |     pub fn to_point(&self, pts: &[Point2<Real>]) -> Point2<Real> {
   |                     ^^^^^
   |
   = help: consider choosing a less ambiguous name
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#wrong_self_convention
   = note: `#[warn(clippy::wrong_self_convention)]` on by default

Fixed by taking full ownership of self (It's not a big deal because they are Copy.