Fix: delay and repeat custom prop support on base class

[allanemerson]

Fixes #1544

From the docs: Since version 4, Animate.css uses custom properties (also known as CSS variables) to define the animation's duration, delay, and iterations.

However, only animation-duration is defined on .animated currently , so defining delay and repeat props on the element or at :root have no effect unless you add one of the modifier classes.

It would be possible to add the delay-1s and repeat-1 classes to trigger the expected behavior, but then you might get a mismatch between the prop value (say you pass in 1.5s on one element and 2 repeats on another, etc).

By adding animation-delay and animation-iteration-count on the base class, explicit control can be set on each element and globally.