feat: Add user configuration for all providers

[dlipovetsky]

• Defines a cluster-level variable for defining one or more users
• Patches bootstrap templates for control plane and worker node pools with user configuration
• Derives value of CABPK's User.LockPassword

[jimmidyson]

Few nits but looking good!

[dkoshkin]

LGTM

[dlipovetsky]

I changed the fixup commit messages to make them conform to the precommit linter, then force-pushed.

[dlipovetsky]

precommit fails because markdownlint complains about line length >= 120 chars in the documentation I wrote.

While maximum line length make sense for a programming language, I think it makes less sense for prose:

1. The docs are written in a text editor, and almost any editor can automatically wrap lines. I don't want to manually wrap lines the first time, or re-wrap lines as I update prose.
2. The docs are read in a browser and a text editor. Almost any browser or editor can automatically wrap lines. Manual wrapping can make it more difficult to wrap text automatically for a given viewport size.

I'd like to remove the rule, and eventually revert all docs to automatically wrapped lines.

[dkoshkin]

I'd like to remove the rule, and eventually revert all docs to automatically wrapped lines.

Thanks, I support this.

[dlipovetsky]

I'd like to remove the rule, and eventually revert all docs to automatically wrapped lines.

Thanks, I support this.

Thanks, I filed nutanix-cloud-native#480.