Add support for dashed and dotted lines in Timeline

[Youcef-Goudjal]

Summary

This PR adds support for dashed and dotted lines in the TimelineDivider component. It introduces new properties to enable dashed and dotted line styles and implements a CustomPainter to handle the custom drawing.

Enhanced Line Styling:

Added support for dotted and dashed lines in both tile.dart and timeline_divider.dart. This includes new parameters for controlling the appearance of dotted and dashed lines, such as dotRadius, dotSpacing, dashLength, and dashSpacing. These changes allow for more customizable timeline appearances.

Usage

To use a dotted or dashed line, set the corresponding properties:

TimelineDivider(
  axis: TimelineAxis.horizontal,
  thickness: 2,
  begin: 0.0,
  end: 1.0,
  color: Colors.grey,
  isDotted: true,
  dotSpacing: 4.0,
  dotRadius: 2.0,
  isDashed: false,
  dashLength: 4.0,
  dashSpacing: 4.0,
)