module suggestion: saving figure

For *ggplot2* graphics, it is tempting to render the plot in shiny using *plotly*. Good for data exploration, but bad for saving graphics. It would be good to have a module that will offer an optional 'interactive graph', and when non interactive renders the simple ggplot2 object, with an option to save as svg, pdf, etc.

No files or tests are named. Start by reviewing the repository's existing Shiny helpers and the ggplot2 and plotly rendering flow; done means a module can optionally provide an interactive graph, render a non-interactive ggplot2 object, and support saving formats such as SVG and PDF.

Written by the indexing model from the issue text.