Refactored shader loader and updated rendering pipeline. Formatted the code for better readability, made the DemoShaderLoader implementation safer than before, and rewrote the code using modern C++ practices to ensure every line is easy to understand.

[Dhaval572]

Refactored demoShaderLoader for improved naming consistency and modern C++ practices. Replaced legacy OpenGL pipeline in main.cpp with VAO/VBO and programmable shaders, updating to OpenGL 4.6 core profile. Added new Sample.vert and Sample.frag shaders, removed old vertex.vert and fragment.frag. Updated resource handling in CMakeLists.txt for relative paths. Minor improvements to openglDebug.cpp formatting.