CLOUDP-344788: add auth command

[blva]

Proposed changes

Jira ticket: CLOUDP-344788

❯  ./bin/atlas auth token --help
Return the token for the current profile.

Usage:
  atlas auth token [flags]

Examples:
  # Return the token for the current profile:
  atlas auth token

  # Return the token for the current profile and save it to a file:
  atlas auth token > token.txt

  # Return the token for a specific profile:
  atlas auth token --profile <profile_name>


Flags:
  -h, --help            help for token
  -o, --output string   Output format. Valid values are json, json-path, go-template, or go-template-file. To see the full output, use the -o json option.

Global Flags:
  -P, --profile string   Name of the profile to use from your configuration file. To learn about profiles for the Atlas CLI, see https://dochub.mongodb.org/core/atlas-cli-save-connection-settings.

Checklist

• I have signed the MongoDB CLA
• I have added tests that prove my fix is effective or that my feature works
• I have added any necessary documentation in document requirements section listed in CONTRIBUTING.md (if appropriate)
• I have addressed the @mongodb/docs-cloud-team comments (if appropriate)
• I have updated test/README.md (if an e2e test has been added)
• I have run make fmt and formatted my code

Further comments

[cveticm]

LGTM, tested locally also 🚀