Update PersistentStore api (#11538)

- Clean up the API to use a `static` class instance to adhere to Marlin convention
- Add `const` position data access for read/write
- Add Storage capacity to the interface

Marlin/src/HAL/HAL_LPC1768/include/Arduino.h

@@ -43,8 +43,6 @@
 #define FALLING      0x03
 #define RISING       0x04
 
-#define E2END 0xFFF // EEPROM end address
-
 typedef uint8_t byte;
 #define PROGMEM
 #define PSTR(v) (v)