feat: add eos_slot_manager.h header for extern slot functions

Author: srpatcha

include/eos_slot_manager.h

@@ -0,0 +1,17 @@
+#ifndef EOS_SLOT_MANAGER_H
+#define EOS_SLOT_MANAGER_H
+
+#include "eos_types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int  eos_slot_scan_all(void);
+bool eos_slot_is_valid(eos_slot_id_t slot);
+int  eos_slot_erase(eos_slot_id_t slot);
+
+#ifdef __cplusplus
+}
+#endif
+#endif