Bug 331345

Setting up and removing new favorite brush presets is a bit lengthy and unintuitive. I propose the following changes to improve it:

- To add a new favorite tool, the user could be made able to right click on one of them in the brush presets docker and select a "add to tool palette" or "add to favorites" option from the popup menu, for quicker favorite tool management.

- Likewise, a "remove from tool palette" or "remove from favorites" could be added in the same pop-up menu, if applicable.

- In the brush presets docker, a small icon could be added to denote which presets are favorite. I propose a little heart-shaped icon. In this way one could tell at a glance which presets have been made favorite without accessing the tool palette or the favorite tools menu (which is a bit hard to access).

- In the tool palette (default shortcut: right click on the canvas), a key combination could be added to remove tool presets directly from there. I propose SHIFT+left click, although it could be anything else. While the SHIFT key is being pressed, the cursor could change shape to indicate that a destructive operation is about to be performed.

- Not related to this improvement proposal, but the same could apply to colors. Previously selected colors could be removed in the same way.

- Favorite tool presets in the tool palette could be dragged to change their displaying order.

- Likewise, the same could be made possible in the Settings > 'Select Favorite Presets' dialog window.

- Not exactly related to tool presets, but the tool palette is a bit too much persistent on screen. This can get confusing as the only ways to remove it are by pressing the right click button again or drawing on the canvas. I propose that it gets automatically removed from view if any of the following conditions are met:

-- After a few seconds with no user input.
-- When any interface element outside the canvas gets interacted with.
-- By pressing the ESC key.

Reproducible: Always