Add npx action

[lalalune]

Is your feature request related to a problem? Please describe.

The goal of this is to enable someone to run 'npx eliza' and it would start a default local running instance of eliza that they could interact with through chat, using all local models.

If the user passes a character file, like --characters=<eliza.json>, then it will load that character file. If the characterfile has secrets in it, it will load all of the secrets, as though they had cloned the repo and run npm run dev -- --characters=.json

The result of this feature is that I can run npx @ai16z/eliza and trial locally, or point to a character file and run an agent (or agents)

[roninjin10]

Happy to add this. What is the entrypoint file that needs to run for this?