Create abstracted scale class

[eamars]

The abstracted scale class shall enable:

• Select scale type (or model) from mini 12864 screen.
• Select scale type (or model) from REST interface.

[eamars]

Generated by ChatGPT:

 // Define the template struct
 typedef struct {
    // Function pointers for read and write methods
    void (*read)(void *self);
    void (*write)(const void *self);
    uint baudrate;
} scale_handler_t;