Common: Move version strings to their own header

Ideally Common.h wouldn't be a header in the Common library, and instead be renamed to something else, like PlatformCompatibility.h or something, but even then, there's still some things in the header that don't really fall under that label

This moves the version strings out to their own version header that doesn't dump a bunch of other unrelated things into scope, like what Common.h was doing.

This also places them into the Common namespace, as opposed to letting them sit in the global namespace.

Source/Core/InputCommon/ControllerInterface/evdev/evdev.cpp

@@ -2,10 +2,12 @@
 // Licensed under GPLv2+
 // Refer to the license.txt file included.
 
+#include <cstring>
 #include <fcntl.h>
 #include <libudev.h>
 #include <map>
 #include <memory>
+#include <string>
 #include <unistd.h>
 
 #include <sys/eventfd.h>