feat: multi-validator bash demo

[agouin]

Update README hello world demo to use four validators with storage local in the test/ directory for config and log browsing during test execution.

Perform genesis assembly in isolated working dir, then distribute out to all vals.

Ctrl+C shuts down all processes and cleans test files.

Resolves #3

[mark-rushakoff]

You should run this through shellcheck. I think it's going to complain about most variables being unquoted, not sure if it will have any other issues.

The shell script looks fine aside from probably not shutting down the other validators, but we can fix that later.

I agree that starting the 4 validator case by default is better for demo purposes, but it probably makes sense to still have a make target to start a single validator network, as that is much easier for debugging known issues.

Raising the signal handling up to main.go is the only part that would be better to change now than later, I think.

[mark-rushakoff]

Could you raise this section up to

gcosmos/main.go

Lines 27 to 28 in 629f0ff

	// We should probably use an os.SignalContext for this in order to ^c properly.
	context.Background(),

so that all commands inherit interrupted contexts? And use signal.NotifyContext, which actually exists, unlike the imaginary type I put in the linked comment.

[agouin]

srvcmd.Execute builds it's own context.Background(), so had to copy the Execute function into main.go and make it take a context.

[mark-rushakoff]

We could add a command to block until the seed server is ready, so you don't have to wait extra time if it starts quickly. That is complex enough to warrant a separate PR.