Inline CP437 font and clean MAX7219 header

Move CP437 font data into header as an inline constexpr array (kCp437Font) and provide character dimensions as constexpr. Remove the separate font_cp437.cpp translation unit. Update copyright/year and tweak file comment. Clean up Max7219Matrix API by removing the Rotate declaration and removing unused font_size_ and font_ members.

Author: vanvught

lib-device/include/max7219matrix.h

@@ -55,12 +55,9 @@ class Max7219Matrix : public MAX7219 {
     void UpdateCharacter(uint32_t c, const uint8_t bytes[8]);
 
    private:
-    uint8_t Rotate(uint32_t r, uint32_t x);
     void WriteAll(uint8_t reg, uint8_t data);
 
    private:
-    uint32_t font_size_;
-    uint8_t* font_;
     uint16_t count_{4};
 };