voids request - Move the filesystem files to root/ as it will be used in both Minecraft.Client and Minecraft.World (#819)

* Move Filesystem to root/include/ as per devoiders request

* Filesystem -> lce_filesystem

include/lce_filesystem/lce_filesystem.h

@@ -0,0 +1,6 @@
+#pragma once
+
+bool FileOrDirectoryExists(const char* path);
+bool FileExists(const char* path);
+bool DirectoryExists(const char* path);
+bool GetFirstFileInDirectory(const char* directory, char* outFilePath, size_t outFilePathSize);