hos: refactor fss to pkg3

To `fss0` config is now renamed to `pkg3`.
`fss0` still works but is deprecated.
Additionally `fss0experimental` key is now renamed to `pkg3ex`

bootloader/hos/pkg3.h

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2019-2021 CTCaer
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _PKG3_H_
+#define _PKG3_H_
+
+#include "hos.h"
+
+int parse_pkg3(launch_ctxt_t *ctxt, const char *path);
+
+#endif