Path Actions and Curves

[AshishS-1123]

Summary / How this PR fixes the problem?

The following features have been added to the Vector tool.

• [x] Double click a ModelTypePath to enter PathEditMode.
• [x] When creating paths, press Backspace to delete the last inserted point.
• [x] Create Curves.
• [x] Rotation of Path should draw points in PathEditMode correctly.
• [x] Show live effect when drawing lines and curves

Steps to Test

Drawing Curves

• To draw curve, first click somewhere to create your first control point.
• Without releasing the mouse button, drag your cursor. This will create the tangent.
• When you are satisfied with the first half of the curve, release the mouse button to signify end of first half.
• Then click somewhere else for your final control point.
• When you are doing all this, you will see a live curve in black color that indicates what your curve might look like.

Deleting Points

• Draw a path using either lines or curves.
• Then press BackSpace to delete points.
• For lines, the line will be deleted as expected. For curves, each of the control points will be deleted in reverse order of creation.
• If you delete all the points in the Path, the Instance gets deleted automatically and PathEditMode ends.

You can also double click on a Path to enter PathEditMode. Doing so will show all the control points in blue dots.

Screenshots

Known Issues / Things To Do

1. Couldn't figure out how to scale paths properly in Transform mode. Will work on that later.
2. Feature to move points around using the mouse, or adding new points between existing will also be handled in the next PR.

[Alecaddd]

From testing this it looks and behaves very well. I will defer the final review to @mbfraga as he has a better understanding of this whole code.

[Alecaddd]

This looks very good as initial step towards a great path tool. Thank you so much.