fs.mitm: WIP LayeredFS impl (NOTE: UNUSABLE ATM)

Also greatly refactors libstratosphere, and does a lot of other things.
There is a lot of code in this one.

stratosphere/fs_mitm/source/fsmitm_layeredrom.hpp

@@ -0,0 +1,31 @@
+#pragma once
+#include <switch.h>
+#include <stratosphere.hpp>
+
+#include "fsmitm_romstorage.hpp"
+#include "fsmitm_romfsbuild.hpp"
+#include "fsmitm_utils.hpp"
+
+
+/* Represents a merged RomFS. */
+class LayeredRomFS : public IROStorage {
+    private:
+        /* Data Sources. */
+        std::shared_ptr<RomInterfaceStorage> storage_romfs;
+        std::shared_ptr<RomFileStorage> file_romfs;
+        /* Information about the merged RomFS. */
+        u64 title_id;
+        std::shared_ptr<std::vector<RomFSSourceInfo>> p_source_infos;
+
+        LayeredRomFS *Clone() override {
+            return new LayeredRomFS(*this);
+        };
+                
+    public:
+        LayeredRomFS(std::shared_ptr<RomInterfaceStorage> s_r, std::shared_ptr<RomFileStorage> f_r, u64 tid);
+        virtual ~LayeredRomFS();
+        
+        Result Read(void *buffer, size_t size, u64 offset) override;
+        Result GetSize(u64 *out_size) override;
+        Result OperateRange(u32 operation_type, u64 offset, u64 size, FsRangeInfo *out_range_info) override;
+};