Allow mods to be loaded from extracted disk files

Also just some code cleanup

src/dusk/modding/bundle_disk.cpp

@@ -0,0 +1,54 @@
+#include <utility>
+
+#include "dusk/io.hpp"
+#include "mod_loader.hpp"
+
+namespace fs = std::filesystem;
+
+namespace dusk::modding {
+ModBundleDisk::ModBundleDisk(fs::path root) : root_path(std::move(root)) {}
+
+std::vector<u8> ModBundleDisk::readFile(const std::string& fileName) {
+    const fs::path filePath = reinterpret_cast<const char8_t*>(fileName.c_str());
+    const auto finalPath = root_path / fileName;
+
+    return io::FileStream::ReadAllBytes(finalPath);
+}
+
+std::vector<std::string> ModBundleDisk::getFileNames() {
+    std::vector<std::string> files;
+
+    std::error_code ec;
+    for (fs::recursive_directory_iterator it(root_path,
+             fs::directory_options::skip_permission_denied |
+                 fs::directory_options::follow_directory_symlink,
+             ec);
+        it != fs::recursive_directory_iterator(); it.increment(ec))
+    {
+        if (ec) {
+            break;
+        }
+
+        if (!it->is_regular_file()) {
+            continue;
+        }
+
+        const auto& path = it->path();
+        const auto relPath = fs::relative(path, root_path);
+        auto string = io::fs_path_to_string(relPath);
+        if constexpr (fs::path::preferred_separator != '/') {
+            // Convert \ to / on Windows
+            for (auto& chr : string) {
+                if (chr == fs::path::preferred_separator) {
+                    chr = '/';
+                }
+            }
+        }
+
+        files.emplace_back(std::move(string));
+    }
+
+    return files;
+}
+
+}  // namespace dusk::modding