Allow list the following yml settings in ECH and Docker

[mikecote]

We should allow list the following yml settings for alerting and task manager in ECH and Docker

Alerting:

• xpack.alerting.maxScheduledPerMinute

Task Manager:

• xpack.task_manager.capacity
• xpack.discovery.active_nodes_lookback
• xpack.discovery.interval
• xpack.task_manager.kibanas_per_partition
• xpack.task_manager.claim_strategy

If there are any other that might be missing in this list regarding the 10x efforts, we should include them as well.

[elasticmachine]

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