Make Instructions for Creating an Executable Publicly Available

[Zach-Attach]

In the README.md, the first step for "Running a NETT" currently does not have linked written or video instructions for creating an executable.

[desaibhargav]

Hi @Zach-Attach, creating an executable would require access to the Unity codebase, which we want to keep locked as of now. Once we have the executables hosted, I will update the README.md to the link to the page where users can download them from.

[Zach-Attach]

Splitting into 2 issues:

1. (this one) will be for creating executables (version 0.3 or later)
2. linking to existing website for hosting premade executables (version 0.2)
   Add Link to Existing Executables #32