Select objects to export[ENH]

[arjohnson77]

The ability to select objects when exporting a PVA to Bot would be very helpful.
For instance, I have a client who will be providing the actual text / conversation-type content for the bot, but doesn't need to know the technical details (creation of variables, etc.).

Currently, when creating the Visio doc from PVA, the only option is to export everything -- which is very helpful, if you want a full document of the flow. However, in this case, I'm only looking for the textual messages.

I plan to delete the technical content that isn't needed from my copy of the document, but the capability to select types would be nice to have if at all possible.