Extending the keyboard usage to element selection and modification

Extending the keyboard usage to element selection and modification: I would like to expand upon @frantic's proposal on #3100 and also suggest that the keyboard usage could be extended to directly select and modify elements in the canvas as well. While we all use Excalidraw to precisely... *draw*, I think there is room for a great improvement if we are able to quickly point to elements we would like to work upon.