Export Map to HTML zipfile

[kylebarron]

Optionally export data into a folder so the Parquet data can stay in binary form. Note that the output directory then needs to be served, it can't be opened as a file.

[kylebarron]

As more context on this issue:

Right now, we always export all the code and all the data into a single massive HTML file, where the binary buffers are Base64-encoded and saved as big strings. This is a pretty good compromise because it's very simple for end users while also being generally foolproof. You can move the file to another machine, double click on it (opening it as a file:// url) and it'll just work.

I was talking to @batpad and he mentioned that having a directory of files might be convenient in some situations. This would allow for some separation between the original data and the code.