Update installation instructions and create a downloadable release

[dmuth]

I have some old instructions from my pre-webpack days in the README:

"Yes. Feel free to clone this repo with git clone https://github.com/dmuth/diceware.git and run it from a local directory on your computer.

You can also set up a webserver on Mac/Linux boxes by running python3 -m http.server 8000. You will then able to access DiceWare at http://localhost:8000/."

I need to create a release, and then replace those instructions.

[dmuth]

Added a release and updated documentation.