[IOT-2358] Add support for GIGA

[robgee86]

Motivation

This PR adds GIGA boards support to the arduino-cloud-cli.

Change description

• Added support for provisioning GIGA boards
• Minor doc fix

Additional Notes

Jira issue: https://arduino.atlassian.net/browse/IOT-2358

Reviewer checklist

• [ ] PR address a single concern.
• [ ] PR title and description are properly filled.
• [ ] Changes will be merged in main.
• [ ] Changes are covered by tests.
• [ ] Logging is meaningful in case of troubleshooting.
• [ ] History is clean, commit messages are meaningful (see CONTRIBUTING.md) and are well formatted.