Bootstrap Screen. Add size 'Extra Large'

core.less

/**
 * BOOTSTRAP: SIZE EXTRA LARGE
 */
@screen-xl-min:                 1480px;
@screen-lg-max:                 (@screen-xl-min - 1);

@container-extra-large-desktop: ((1420px + @grid-gutter-width));
@container-xl:                  @container-extra-large-desktop;

@modal-xl:                      1100px;

.container {
  @media (min-width: @screen-xl-min) {
    width: @container-xl;
  }
}

@media (min-width: @screen-xl-min) {
  .make-grid(xl);
}