Fixes a macOS Metal crash when stopping immediately after boot starts.

m_upload_encoder and m_texture_upload_encoder could be dealloc'd during shutdown before endEncoding could be called, which causes a Metal assertion failure.

Co-authored-by: OatmealDome <julian@oatmealdome.me>

Move the constructor and destructor after the definition of the class
`Internal`.

This fixes an error generated by Clang from the destructor of
`std::unique_ptr<Internal>` when setting the standard version to c++23:

`invalid application of 'sizeof' to an incomplete type 'Metal::ObjectCache::Internal'`.

VideoBackends / VideoCommon: add support for specifying include files in shader code

Make the function name more explicit and a better match for
GetDisplayName.

Change NAME to CONFIG_NAME while I'm at it.