Add hourglass animation to the LED matrix gallery

[alranel]

No description provided.

[aentinger]

Minimal example sketch to test this:

#include "Arduino_LED_Matrix.h"

ArduinoLEDMatrix matrix;  

void setup() {
  matrix.loadSequence(LEDMATRIX_ANIMATION_HOURGLASS);
  matrix.begin();
  matrix.play(true);
}

void loop() {
}

[aentinger]

Tested and works 👍