cli: ability to specify a config profile as a flag

[russorat]

when working across instances, sometimes you would like to pull from one and write to another. it would be great if you could do something like:

influx query "from" --config dev | influx write --config prod

or

influx export stack $STACK_ID | influx apply --active-config us-west

[jsteenb2]

I'm largely in favor of --active-config with a -c short. The --active-config makes it very clear. And it disambiguates with the places where we have existing --config flags (influx config [cmd] commands)