Improved number of lines calculation

[Juanpe]

Summary

The goal of this PR is to improve how the number of lines for text nodes is calculated. Until now, the library decided to use the value of the numberOfLines property. Now, exist a new type to define how the library should calculate the number.

Before

You could set the number of lines by setting the numberOfLines property:

label.numberOfLines = 2

/// Both the label and the skeleton have 2 lines

After

Now, you can be more specific:

label.numberOfLines = 2
label.skeletonTextNumberOfLines = 1

/// The label has 2 lines but the skeleton has only one.

Here the SkeletonTextNumberOfLines definition:

enum SkeletonTextNumberOfLines {

    /// Returns `numberOfLines` value.
    case inherited

    /// Returns the specific number of lines specified as the associated value.
    case custom(Int)

}

[github-actions[bot]]

	Warnings
:warning:	Consider **also** updating the README for other languages.

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