aoscx_checkpoint: add auto-checkpoint (confirmed commit) timer support

[ed6869]

Fixes #225

Summary

Extends the existing aoscx_checkpoint module with two options to manage the auto-checkpoint (confirmed commit) timer, mapping 1:1 to the AOS-CX CLI:

• auto: start + auto_timeout: <1-60> -> checkpoint auto <minutes>
• auto: confirm -> checkpoint auto confirm

When auto is set, source_config/destination_config are ignored. If the configuration is not confirmed before the timer expires, the switch automatically rolls it back — ideal for safe remote deployments (auto-rollback on lost connectivity).

Backed by the pyaoscx Configuration SDK methods, no raw REST in the module.

Example

- name: Arm a 2-minute auto-checkpoint before a risky change
  arubanetworks.aoscx.aoscx_checkpoint:
    auto: start
    auto_timeout: 2

- name: Confirm and keep the configuration
  arubanetworks.aoscx.aoscx_checkpoint:
    auto: confirm

Testing

Live-tested on a CX6300 (FL.10.17): start + confirm keep the change; without confirm the switch auto-rolls back. flake8, pep8, pylint and validate-modules all pass.

Depends on

SDK PR aruba/pyaoscx#114 (adds Configuration.set_auto_checkpoint / confirm_auto_checkpoint).