[CLI] Add command for `get_alerts_over_time`

[epalhares-tenchi]

Description

Expose a new CLI command that wraps the get_alerts_over_time method from the SDK.

Expected

• New command that calls get_alerts_over_time
• Accepts:
  • --organization-id (required)
  • --following-ids (optional, list)
  • --severities (optional, list)
  • --dates (optional, list)
• Uses existing SDK method
• Supports JSON output