Add `atlas::material_table` to manage large storage of textures.

[mrparmesan01]

The way we would have our textures loaded into the shaders are having one large array of textures that each index represents as different slot for accessing those textures.

Problem Statement

If we have multiple 3D meshes that may utilize the same texture or material specified. We should not need to load the same texture to take up another slot (location) in that large texture array.

Really, should be reusing that same texture already available to use rather then loading the same duplicate texture entirely.

This will involve defining what a material consists of. Here are some basic definitions for defining a material.

struct material {
   glm::vec4 albedo;
   glm::vec3 specular;
   glm::vec3 diffuse;
   float roughness;
   float metallic;

   // set to optional because they may not have a texture loaded with them.
   std::optional<vk::sample_image> albedo;
   std::optional<vk::sample_image> diffuse;
   std::optional<vk::sample_image> specular;
   std::optional<vk::sample_image> normal;
   std::optional<vk::sample_image> parallax;
};

Completion of the Task

We should be able to load multiple 3D meshes and each of them using the same texture. That does not need to involve having to load in the new texture and automatically reuse the texture image available in GPU memory.

[mrparmesan01]

Additional Thoughts

Something that would be useful to have is rather then having a material table, there is an external storage to pull from. Where we not only are able to retrieve the texture data itself, we can also retrieve the indices for accessing them.

This way if we have a lot of additional textures. We remove the duplicates and can have this large texture array be used to ensure that we dont load duplicate tetxures and just simply assign the textures index to the material that is using that particular texture.