functions declared in ui.h were actually used by ui.c, the opposite of
what such a header is expected to contain. these functions are defined
in zig code and declarations are better off in the same ui.c file.
this is just a quick clean up before porting some C code to zig.
the idea is for all zig code to use C LVGL only via this
new module lvgl.zig, all display and input driver/devices is handled
by drv.zig.
this makes C/zig nicely compartmentalized in just a handful places.
16px looks easier to read but IPv6 addresses don't fit in the wifi
settings panel anymore. need to find a better way how to display them or
change font.
alex