Added CLI arguments for aws-okta add

[vivianho]

• Added CLI arguments for Okta organization (deprecated?), Okta region, Okta domain and Okta username. Reason: We would rather give our employees a single simple command to run already configured with our company's variables, rather than tell them "when you see this prompt, type this"
• Updated oktaDomain example value to ["+organization+".okta.com] because after reading the code it seems like this is actually the format that is derived, not "+region+".okta.com.
• Included a log line for the oktaDomain to verify this
• Indentation fixes

[nickatsegment]

Thanks @vivianho!

FYI, organization is deprecated in OktaCreds/Client because it's superfluous. Domain is all it really cares about. There's compatibility code in there, but we should avoid using it.

[nickatsegment]

I've been meaning to do this for ages and it'd help immensely. The interaction between flags and prompts is subtle though and needs some care to avoid double prompting.

[vivianho]

@nickatsegment your comments make sense to me. I'm trying to think about the simplest way forward here. Options:

1. Command line only takes in --domain, and organization/region is calculated from this. (edit: it seems like organization/region values are not actually needed at all following the NewOktaClient code, so we can just leave them blank?)
2. Command line only takes in --region and --organization and domain is calculated from this.

It seems like 2) would be simpler (with the code that is already provided) however 1) seems to be the desired approach given that organization is deprecated?

1. seems like a better approach given that we don't even need the region/organization name at all?

[vivianho]

I refactored with some new changes.

[nickatsegment]

I like this approach. Great job.