Draft: libgimp, menus, groups, pdb, core, actions, widgets, app: Toggle the active tool to the eraser tool
This MR creates a procedure in the pdb to toggle the current tool to the Eraser. A shortcut can then be applied to this action so that the user can toggle to the eraser whilst painting, and back again to whatever tool they were painting in.
This is could be an answer to this -> https://gui.gimp.org/index.php?title=Usability_and_Tools