Remove StatusBar, replace with discoverable tooltips on overlay

## Context
The purpose of the Bottom StatusBar was to have a place to list "tips and hints" for tools, not easily discoverable via accelerators.
For example, when the user selects the Rectangle Tool, the follow message will appear: `Hold **Ctrl** to keep a 1:1 ratio of width and height | Hold **Shift** to grow from center point`

## Proposal
- Removing the StatusBar to have a cleaner UI and gain more space.
- Show the "hints" as an overlay widget in the bottom left corner of the Canvas area.
- Allow users to hide the "hints" from the Preferences Panel (great for expert users who don't need "tutoring")

## Screenshot example