Support export of project to a directory of HTML, CSS, and JS files

[davidfstr]

For archival purposes it would be nice to be able to export a downloaded website not as a .crystalproj (which requires a Crystal binary to view it) but rather as a set of plain files in the filesystem.

However a website exported in this way only works reliably for traditional static websites.

Priority: Low

• Many websites exported using this technique (which aren't entirely static) won't load/display correctly using this technique. Therefore prefer other more-robust export techniques over this one:
  • -> Support export of project to a self-contained binary web server (best local alternative)
  • -> Support export of project to static file server (like GitHub Pages) (most similar hosted alternative)