standalone release

[garfieldnate]

It would simplify the Soar release and enable quicker feature delivery if we could release VisualSoar by itself as a standalone executable or installer. We already have gradle tasks for this using jpackage and/or jlink, but there are some remaining issues:

• Soar cannot be loaded because the library can't be located. Fixing this will require adding a workflow for the user to specify where Soar is. In the standalone context, we don't get to use an environment variables, so setting SOAR_HOME doesn't work!
• Fix icon. Below you'll see the old and new apps side by side:
  . I don't know why setting the icon from the AWT API doesn't work. Here's an example of setting the icon through jpackage (and other metadata): https://github.com/beryx-gist/badass-jlink-example-richtextfx/blob/master/build.gradle#L26
• Ensure chosen release method works and create release instructions. For example, I don't think the installers generated for Windows work, and I don't know why.