allow provider-specific args in the cli

[codefromthecrypt]

currently, in order to specify credentials, we have to use the abstract -c flag for each part.

ex. denominator -p ultradns -c username -c password zone list

If we instead group on provider, we can detect what the exact values should be.

ex. denominator route53 --accessKey ... --secretKey ... zone list

In this case, airline would read Provider.defaultCredentialSupplier() to see if args are even required, or Provider.getCredentialTypeToParameterNames() to see what the argument names should be.

[jdamick]

+1

[codefromthecrypt]

via @kiall

It's "normal" for OpenStack APIs to need to specify the region you want to interact with, so having that as a config option would be the norm

[brianm]

Can I get unassigned from this?