Support for Polish OLED characters

Added support for Polish OLED characters.

- Custom FONT_SMALL ArialMT_Plain_10_PL

- Automatic selection between Polish and Ukrainian/Russian characters mapping depending on the -D OLED_{LANG_NAME} flage

src/graphics/fonts/OLEDDisplayFontsPL.h

@@ -0,0 +1,11 @@
+#ifndef OLEDDISPLAYFONTSPL_h
+#define OLEDDISPLAYFONTSPL_h
+
+#ifdef ARDUINO
+#include <Arduino.h>
+#elif __MBED__
+#define PROGMEM
+#endif
+
+extern const uint8_t ArialMT_Plain_10_PL[] PROGMEM;
+#endif