feat: allow maintaining shape when dragging coordinates in select mode

[JamesLMilner]

Description of Changes

Provides a new option maintainShapeFrom in select mode in the feature -> coordinate property. The possible options are:

• 'center' - the shape is maintained with it's origin at the center
• 'opposite' - the shape is maintained with the origin as the opposite bounding box point

This is how you use it:

		new TerraDrawSelectMode({
			flags: {
				polygon: {
					feature: {
						draggable: true,
						rotateable: true,
						scaleable: true,
						coordinates: {
							midpoints: true,
							draggable: true,
							deletable: true,
							maintainShapeFrom: "center"
						},
					},
				},

This PR also fixes the fact that E2E tests were not actually running.

Link to Issue

#183 #184

PR Checklist

• There is a associated GitHub issue
• If I have added significant code changes, there are relevant tests
• If there are behaviour changes these are documented