Pinhole component: a union of different representations

[emilk]

log_pinhole takes a focal_length_px argument and then directly converts it into a 3x3 matrix. Instead we should rewrite the Pinhole component as something similar to:

enum Pinhole {
    Matrix(PinholeMatrix),
    Params(PinholeParams)
}

struct PinholeMatrix {
    pub size: Vec2,

    pub child_from_parent: Mat3
}

struct PinholeParams {
    pub size: Vec2,

    pub focal_length_px: Vec2,

    /// Default: center
    pub principal_point_px: Option<Vec2>,
}

[emilk]

• Actually: #6388

So we need some other design for this