Add Support for Orthographic Camera

[randomPoison]

This feature would be useful for working on the grid collision system since I'm testing it in a 2D plane and the perspective makes it hard to visually verify that a collision took place. Orthographic projection is also needed for better 2D support down the line, so it's worth getting in now.

[randomPoison]

Some notes for anyone looking to complete this task: The camera code can be found in lib/polygon_rs/src/camera.rs. Currently there is a single Camera struct that represents a perspective camera. The Camera type should be turned into a enum with variants Perspective and Orthographic. The current Camera type should be renamed PerspectiveCamera and a new type OrthographicCamera should be added. Camera::Perspective should contain a PerspectiveCamera object and Camera::Orthographic should contain an OrthographicCamera object. The new Camera enum should have three functions implemented for it: view_matrix(), inverse_view_matrix(), and projection_matrix() which should return the specified matrix based on the camera variant (either perspective or orthographic). In terms of the rendering system things should just work with those changes as the renderer only accesses the camera's matrices through those three public methods.

~~This change will require some slight reworking within the component system as well. In src/component/camera.rs gunship defines a custom camera type that removes the redundant position and orientation members from polygon's Camera. The Camera component will need to be reworked in the same way that polygon's Camera was, making it into an enum with two variants.~~

The hardest part is likely going to be getting the math right, however there are plenty of tutorials and documents online that explain the math needed to complete this task. If you don't have an understanding of linear algebra and projection matrices you might be able to still complete this task but it will take much longer.