Feature request

Service to disable/enable for collision_monitor

Feature description

The collision_monitor plugin is an awesome and much needed feature in a variety of industrial service robot use cases.
As implemented in humble, it does not offer an interface to disable or enable it AFAIK?
There are a number of use cases where disabling and enabling the colliion monitor plugin, e.g from a behavior tree can be useful:

1. Robot needs to dock with a charger, or a payload
2. Robot has to get very close to an object, for inspection.

Implementation considerations

A ros2 service call to set "enable" or disable" with additional checks for security:

1. Returns failure if collision monitor is in an active "slowdown" or "stop" state