Add Model Versions for all the saved objects in task_manager, alerting and actions plugins

[ersin-erdal]

This is a meta issue.

As modem versions are replacing migrations and we start to use them for validation we should have modelVersions for all the saved object we have.

Task Manager

saved objects

• [x] task

Alerting

saved objects

• [x] alert
• [ ] api_key_pending_invalidation
• [ ] rules-settings
• [ ] maintenance-window
• [x] ad_hoc_run_params

Actions

saved objects

• [x] action (PR)
• [x] action_task_params (PR)
• [ ] connector_token

[elasticmachine]

Pinging @elastic/response-ops (Team:ResponseOps)