Rename storage.? -> config.?

The "storage" source code files contained lots of stuff with "config" in
the name, but nothing named "storage".  This was unlike every other part
of the firmware, so I renamed the files to "config".

src/storage.c → src/config.c

  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "storage.h"
+#include "config.h"
 
 #include "chprintf.h"
 

src/storage.h → src/config.h

  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef PDB_STORAGE_H
-#define PDB_STORAGE_H
+#ifndef PDB_CONFIG_H
+#define PDB_CONFIG_H
 
 #include <stdint.h>
 
 struct pdb_config *pdb_config_flash_read(void);
 
 
-#endif /* PDB_STORAGE_H */
+#endif /* PDB_CONFIG_H */

src/device_policy_manager.c

 #include <hal.h>
 
 #include "led.h"
-#include "storage.h"
+#include "config.h"
 #include "pd.h"
 
 

src/shell.c

 #include "chprintf.h"
 
 #include "usbcfg.h"
-#include "storage.h"
+#include "config.h"
 #include "led.h"
 #include "device_policy_manager.h"
 #include "policy_engine.h"