[Base] Split of xbox.h file

- Splitted into: kernel.h and xam.h
- Removed UpdateSpaData from KernelState into ContentManager

src/xenia/kernel/xam/content_manager.h

@@ -20,6 +20,7 @@
 #include "xenia/base/mutex.h"
 #include "xenia/base/string_key.h"
 #include "xenia/base/string_util.h"
+#include "xenia/vfs/entry.h"
 #include "xenia/xbox.h"
 
 namespace xe {
@@ -203,6 +204,8 @@ class ContentManager {
       const uint64_t xuid,
       uint32_t base_title_id = kCurrentlyRunningTitleId) const;
 
+  bool UpdateSpaData(vfs::Entry* spa_file_update);
+
   KernelState* kernel_state_;
   std::filesystem::path root_path_;