Request to Add Leaflet Browser Print

[nschwamm]

This is similar to other's questions to add a printing/exporting based leaflet extension. This is a clear limitation from the actual integration of the leaflet project because it limits the ability to actually export the maps to a 3rd party. The preference towards Browser Print (vs other plugins discussed) is that it better supports the auto option for size, thus making it more robust in it's usage. For example, when using Shiny, the ability to auto resize is crucial.

Initial repo: https://github.com/Igor-Vladyka/leaflet.browser.print