GetConfigurer returns the probe configurer specified by name from `Registry`.

Register is called by the `init` function of every `Configurer` to add the caller to the global `Registry` map.

Registry is the global mapping of all `Configurer` types.

Configurer is the interface for `Configurer` types.

Prober is the interface for `Prober` types.

Settings is exported as a temporary receiver for the `settings` field of `MonConf`.