feat: Add support for create/update/delete/get/list tasks and cleanup policies

[xino12]

After merge of datadrivers/go-nexus-client#173 and some other changes related to cleanup policies

Add task and cleanup policy support.

[jtnord]

fixes: #200

[draxxris]

Running the example against Nexus 3.78.2-04, I am getting HTTP 405

resource "nexus_task" "example" {
  name                   = "example-task"
  type                   = "repository.cleanup"
  enabled                = true
  alert_email            = "alert@example.com"
  notification_condition = "FAILURE"
  frequency {
    schedule       = "daily"
    start_date     = 1633046400000
    time_zone_offset = "UTC+0"
    recurring_days = [1, 2, 3]
    cron_expression = "0 0 * * *"
  }
  properties = {}
}

2025-07-22 15:27:24,992+0000 ERROR [qtp78227576-15852]  admin com.sonatype.analytics.internal.filter.AnalyticsMeteringFilter - Error metering request RESTEASY003650: No resource method found for POST, return 405 with Allow header
2025-07-22 15:27:24,992+0000 WARN  [qtp78227576-15852]  admin org.sonatype.nexus.siesta.internal.WebappExceptionMapper - (ID 2cb78971-3c75-4cf9-9fa1-5c4ee5aae2e1) Response: [405] (no entity/body); mapped from: javax.ws.rs.NotAllowedException: RESTEASY003650: No resource method found for POST, return 405 with Allow header

[jtnord]

@polski-g there is no repository.cleanup task type. where did you find this task type? you can get all the tasks types from /v1/tasks/templates/

[vivekdhami]

This seems to be still waiting for a review. Would be great if these changes can be merged or commented on if something is missing.

[xino12]

@anmoel could you review these changes please? Thank you

[anmoel]

@xino12 please fix the tests for tasks (see pipeline)

[jtnord]

Skip tests when not running against nexus pro.

The Tasks management endpoints are mostly Nexus Pro only so need to be skipped when not running against a nexus pro instance.