Environment should use coordinates instead of x and y

[swom]

Depends on

• [x] #424

In enviornment.h:

• [ ] Remove memeber functions get_x and get_y
• [ ] Remove the memeber variables m_x and m_y
• [ ] and (if not done for #424) add member variables

  coordinate m_top_left;
  coordinate m_bottom_right;

• [ ] (if not done for #424) repurpose member functions

  const coordinate& get_top_left() const noexcept
  const coordinate& get_bottom_right() const noexcept

  to work with the coordinate new coordinate members

• [ ] create free functions get_max_x/y(const environmnet& e) and get_min_x/y(const environmnet& e).

[TheoPannetier]

There are no get_x() / get_y() or m_x, m_y in environment so solved I guess 👍