GLASM is getting good enough that we can move it out of advanced graphics settings. This removes the setting `use_assembly_shaders`, opting for a enum class `shader_backend`. This comes with the benefits that it is extensible for additional shader backends besides GLSL and GLASM, and this will work better with a QComboBox. Qt removes the related assembly shader setting from the Advanced Graphics section and places it as a new QComboBox in the API Settings group. This will replace the Vulkan device selector when OpenGL is selected. Additionally, mark all of the custom anisotropic filtering settings as "WILL BREAK THINGS", as that is the case with a select few games.