fix: issues with digital ocean and required environment variable versus pulumi value

[qdzlug]

Describe the bug
This is related to #207 but slightly different. It appears that in order for the Pulumi provider to pull the token from the Pulumi config it needs to be both:

• In the digitalocean namespace, as digitalocean:token
• Encrypted.

I have made the first change, but in order to make the second change we are going to need to do a bit more work because of the way we inherit the provider from the superclass for the do module.

As a stopgap, I've noted in the logic when prompting for a key that it should be in the environment.

This - and #207 - both really need to be made a bit more sane given the fact we try and auth three different ways in order to make this work.

To Reproduce
Steps to reproduce the behavior:

1. Deploy on DO w/o setting the DIGITALOCEAN_TOKEN environment variable.

Expected behavior
It should, uh, work.

Your environment
n/a

Additional context
None

[qdzlug]

Note - this is also causing the failure of DO Jenkins build jobs.