refactor: seperated logic in the visualization

Cleaned up the OPENGL 3D protein visualization. Before everything was connected and written in one file, this was to ensure everything worked as intended.

Relevant logic, shaders, and 3D vector math has been seperated, to ensure low coupling, but also to make further additions to the UI more comprehensible.

opengl/shaders/fragment_shader.glsl

+#version 330 core
+out vec4 FragColor;
+
+in vec3 FragPos;
+in vec3 Normal;
+in vec3 vertexColor;
+
+uniform vec3 sphereColor;
+uniform bool useUniformColor;
+
+void main()
+{
+    vec3 color;
+    if(useUniformColor)
+        color = sphereColor;
+    else
+        color = vertexColor;
+    FragColor = vec4(color, 1.0);
+}