Rename --listen-address to --explorer-address

[keturiosakys]

The flag --listen-address is ambiguous as to what exactly will be listening on
that port. We should consider renaming it to --explorer-listen-address or
--explorer-port.

[hatchan]

I don't agree with this, since explorer is only one of the things that we are hosting on the port. I also think that --listen-address or -l is pretty common.

[brettimus]

so this is worth noting because i'd also proposed the same change, independently of lau :)

--listen-address might be common in certain worlds, but my opinion is that a user would more intuitively understand that the --explorer-address is where the explorer would be hosted

[brettimus]

we could... alias (i.e., "why not both")? or is that just confusing?

[keturiosakys]

Ah gotcha - maybe indeed we should have an alias then.

[hatchan]

Closed by #50