Adheres to GL_ARB_separate_shader_objects requirements

Ensures that states set for a particular stage are not attached to other
stages which may not need them.

Silences the following warnings-turned-errors:
-Wsign-conversion
-Wunused-private-field
-Wbraced-scalar-init
-Wunused-variable

And some other errors

This change adds two new context menu items to remove either the OpenGL or the Vulkan shader caches individually, and the provides the option to remove all caches for the selected title.
This also changes the behavior of the open shader cache option. Now it creates the shader cache directory for the title if it does not yet exist.

The current implementation is prone to causing graphical issues. Disable until a better solution is implemented.

Fix regression on Fire Emblem: Three Houses when using native fp16.

Workaround potential bug on Nvidia's driver where only updating high
attributes leaves low attributes out dated.

account for the fact that program.*memory_size is in units of bytes.

Used by MH:Rise

Fixes OpenGL.

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.