Add Slide Direction Enum to Control Slide-In and Slide-Out Direction on `RotateAnimatedText`

## Description

Currently, the Animated-Text-Kit Flutter package provides a great set of animations for text, including the `RotateAnimatedText`. However, it lacks the ability to control the direction of text slide-in and slide-out animations. This enhancement proposes adding a new enum property to `RotateAnimatedText` to allow users to specify the slide direction.

## Motivation

Adding the ability to control the slide-in and slide-out direction of text animations will provide users with greater flexibility and customization options when using the `RotateAnimatedText` widget. It will make the package even more versatile and adaptable to various design requirements.

## Proposed Solution

1. Introduce a new enum called `SlideDirection` at the top of the `RotateAnimatedText` file to control the direction of text slide-in and slide-out animations.

2. Modify the `RotateAnimatedText` constructor to accept a `slideDirection` property of type `SlideDirection`, allowing users to specify the desired slide direction when creating an instance of `RotateAnimatedText`.

3. Update the `initAnimation` method to use the `slideDirection` property to determine the slide direction for both slide-in and slide-out animations.

4. Ensure that the default behavior matches the current behavior for existing users who don't specify a `slideDirection`.

## Additional Information

This enhancement will enhance the capabilities of the Animated-Text-Kit package, making it more versatile and accommodating to a wider range of design requirements. It can be particularly useful for users who want to control the direction of text animations for creative and engaging UI/UX experiences.