[OnWeek] Maintenance Window API

[adcoelho]

Summary

As my On Week project, I wanted to figure out how to support new resources/APIs in the terraform provider.

Change summary

No tests or validation, just a proof of concept.

I generated the documentation for the MW API and merged the bundle with generated/alerting/bundled.yaml in the elasticstack project.

Re-generated mocks.

make generate-alerting-api to update the alerting client in the provider project.

Change the following code:

1. Model - internal/models/maintenance_window.go
2. Client - internal/clients/kibana/maintenance_window.go
3. Resource - ResourceAlertingMaintenanceWindow
   1. ResourceAlertingMaintenanceWindow returns a schema.Resource
   2. implements Create, Read and Delete (Update in the future)

Example

resource "elasticstack_kibana_maintenance_window" "my_maintenance_window" {
  title    = "Foobar Maintenance Window"
  enabled  = true
  start    = "1992-01-01T05:00:00.200Z"
  duration = 3600000

}