Add support for decrypted NCA files (#567)

* Start to add NCA support in loader

* More nca stuff

* More changes to nca.cpp

* Now identifies decrypted NCA cont.

* Game list fixes and more structs and stuff

* More updates to Nca class

* Now reads ExeFs (i think)

* ACTUALLY LOADS EXEFS!

* RomFS loads and games execute

* Cleanup and Finalize

* plumbing, cleanup and testing

* fix some things that i didnt think of before

* Preliminary Review Changes

* Review changes for bunnei and subv

src/core/file_sys/partition_filesystem.h

@@ -37,7 +37,7 @@ public:
 
 private:
     struct Header {
-        std::array<char, 4> magic;
+        u32_le magic;
         u32_le num_entries;
         u32_le strtab_size;
         INSERT_PADDING_BYTES(0x4);