add support for filtering on monitor_tags

[celik0311]

currently you can filter on scope but I dont see any way to filter monitors based on monitor_tags. This would be useful for filtering monitors based on custom tags.

monitor_tags

string

A comma separated list indicating what service and/or custom tags, if any, should be used to filter the list of monitors. Tags created in the Datadog UI automatically have the service key prepended. For example, service:my-app.

source: https://docs.datadoghq.com/api/latest/monitors/