[android/fs] external content loader + nca/xci patches (#3596)

Foreword: WHY DON'T EVERYBODY USE ONE FOLDER FOR EACH GAME+CONTENTS? AIN'T THIS THE FORMAT GAMES COME WHEN YOU BUE THEM? DO YOU LIVE WITH ALL YOUR FRIENDS AND HAVE A 2ND HOUSE FOR ALL THE CHILDREN?

Nice, i feel better now.

This feat extends Maufeat's work on external content loading. It harmonically additions:
"...also, if in each game folder X, you find a folder Y, and in this folder Y you detect ONLY a single game, then mount all external content for that game found in that folder Y and its subfolders."
Permanent (not toggleable). External Content folders are supported equally.

Also:
-Reworked several routines for preserving single source of truth between android and other systems;
-Fixed the annoying unknown format error for content files, by providing proper format detection.

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3596
Reviewed-by: MaranBr <maranbr@eden-emu.dev>
Reviewed-by: Lizzie <lizzie@eden-emu.dev>
Co-authored-by: xbzk <xbzk@eden-emu.dev>
Co-committed-by: xbzk <xbzk@eden-emu.dev>

src/core/file_sys/registered_cache.h

@@ -9,6 +9,7 @@
 #include <array>
 #include <functional>
 #include <memory>
+#include <optional>
 #include <string>
 #include <vector>
 #include <ankerl/unordered_dense.h>
@@ -262,6 +263,8 @@ public:
                   VirtualFile file);
     void AddEntryWithVersion(TitleType title_type, ContentRecordType content_type, u64 title_id,
                              u32 version, const std::string& version_string, VirtualFile file);
+    bool AddEntriesFromContainer(VirtualFile file, bool only_content = false,
+                                 std::optional<u64> base_program_id = std::nullopt);
     void ClearAllEntries();
 
     void Refresh() override;
@@ -276,7 +279,6 @@ public:
 
     std::vector<ExternalUpdateEntry> ListUpdateVersions(u64 title_id) const;
     VirtualFile GetEntryForVersion(u64 title_id, ContentRecordType type, u32 version) const;
-    bool HasMultipleVersions(u64 title_id, ContentRecordType type) const;
 
 private:
     std::map<std::tuple<TitleType, ContentRecordType, u64>, VirtualFile> entries;
@@ -303,7 +305,6 @@ public:
 
     std::vector<ExternalUpdateEntry> ListUpdateVersions(u64 title_id) const;
     VirtualFile GetEntryForVersion(u64 title_id, ContentRecordType type, u32 version) const;
-    bool HasMultipleVersions(u64 title_id, ContentRecordType type) const;
 
 private:
     void ScanDirectory(const VirtualDir& dir);