Was swapping between references and pointers for no reason. Just unify them here since each of these utility functions will need their parameters to be alive.
Previously this could cause problems if a version of the template generated for WriteSetting didn't use the type you needed (e.g. floating point values). Now these are all ready without having to be used within frontend_common first.
On compliant Wayland compositors windows are matched to their .desktop files by comparing the appId window property to the name of the .desktop file without the .deskop extension.
Qt5/6 by default set this property to the basename of the binary (IE `yuzu`) which does not match the expected value `org.yuzu_emu.yuzu`. We can fix this and fix window associations on compliant compositors (like Plasma) by using the `setDesktopFileName()` function which will set the appId window property. This is a no-op on X11 so is safe to be ran without guards.
Replaces every way of handling config for each frontend with SimpleIni. frontend_common's Config class is at the center where it saves and loads all of the cross-platform settings and provides a set of pure virtual functions for platform specific settings.
As a result of making config handling platform specific, several parts had to be moved to each platform's own config class or to other parts. Default keys were put in platform specific config classes and translatable strings for Qt were moved to shared_translation. Default hotkeys, default_theme, window geometry, and qt metatypes were moved to uisettings. Additionally, to reduce dependence on Qt, QStrings were converted to std::strings where applicable.
t895