Tooltips lab: Create tooltip

[blewjy]

On clicking of the Create Tooltip option, 1 of 2 things will occur:

1. If no prior selection, a default callout and trigger shape will be generated.
2. If there is a prior selection, a default callout shape will be generated on top of the selection. Multiple selection will generate multiple callout shapes.

[ChesterSng]

Hi @blewjy good job on the PR!

Is it better to group the callout shape and trigger shape after you generate them (when a user does not select anything and use Create Tooltip), this way it is easier for the user to shift the pair around.