feat: Add toolStyles and DragProbe

[sedghi]

We will start by looking at the style hierarchy. The style hierarchy is as follow.

• Annotation-level settings (with UID) set/getAnnotationToolStyle
  • Viewport-level tool settings set/getViewportToolStyle
    • Per-tool this layer: Length on this viewport
    • Global this layer: All tools in this viewport
      • toolGroup settings (for any tool specified in this toolGroup in all viewports of the toolGroup) set/getToolGroupToolStyle
        • Per-tool layer: Angle on this toolGroup in all viewports
        • Global this layer: All tools in this toolGroup in all viewports
          • Default level: set/getDefaultToolStyle
            • Per-tool layer (Length) settings
            • Global (app-level) settings (we provide a default).

In annotation rendering loop, upon getting a style for a certain property (color, lineDash, lineThickness)
we check whether the style is set at the annotation level (highest priority).
If not, we check whether any viewport-level setting is set (for the viewport annotation is drawing on); however,
in the viewportLevel, we first check whether the tool-level setting is set. If not, we check in the "global" (all tools in the viewport) level.
If not found, we move to the next level for toolGroup level. If not found, we move to the next level for global level which is last
level to check.

Other stuff:

• Add Drag probe
• Fix a bug where textlines changing would not appear

[JamesAPetts]

Minor comments, LGTM, other than type renamings we talked about in meeting.

[JamesAPetts]

Looks good other than the Drag Probe Tool which needs a rethink.

[JamesAPetts]

One change, lets discuss on zoom later today.