Store N in the right variable.
This is too rarely used.

"mea culpa, mea culpa, mea maxima culpa"

Small corrections

On last commit, some strings were ended with the incorrect character.
This fixes it.

Add missing Spanish language definitions.

If the watchdog is enabled and bootscreen + SD card checks take too long, Marlin may hang at boot time because of the reset loop. We have this happen all the time with the Anet board if no SD card is inserted.

Correction to #5629

As a showcase function for how to do waiting in the lcd menu, this function should be preserved.

Use index macro instead of e

delay() is milliseconds

Add missing Spanish language definitions.

Added tarnslation for
```
#define MSG_DEBUG_MENU 
#define MSG_PROGRESS_BAR_TEST
```

I have been a bit too radical in cleaning up this section.

・Add new translation

- Japanese and Chinese still need update

This can already be done via G-Code, so adding the capability to the LCD should be straight forward.

millis_t is long - divisions take for ever.

Return a kind of millisecond instead of microsecond -
divided by 1024 instead of 1000 for speed. (2.4% error)

That does not matter because block_buffer_runtime is
already a too short estimation.
Shrink the return-type.

Fix size for writeData and readData.
For bilinear grid 11 x 11 for example, size is 4 (float) x 11 x 11 = 484. uint8_t max is 255.