Add `gds#find`

Based on feedback from @maxdemarzi, introduce a `gds#find` method that replaces `gds#findNodesByLabelAndProperty` and `ggo#getAllNodesWithLabel`.
Taking pretty generic arguments like String and Object just makes retconning it later harder. So why not spend some time to come with less ad-hoc API? Or keep a rather precise method name like we have now?