Add Mycelium to default config

[jsoares]

Adds the Myeclium subnet with remote glif endpoint to both the default config and the readme. This would make the ipc-cli work out of the box and avoid step 3 in the quickstart. We could also leave it commented out, but this seems strictly better.

Closes consensus-shipyard/ipc#358

@trruckerfling We'll need to update the docs once this makes it to main.

[adlrocha]

I'll let @trruckerfling merge and propagate the changes to the docs.

[jsoares]

@adlrocha I'm going to merge it now because it's immediately helpful, and I think it's also helpful to @trruckerfling and the DX team to have the docs consolidated. Anyhow, changes are notified!