Feat/add blackbox probes library

README.md

@@ -83,9 +83,29 @@ juju config blackbox-exporter-k8s \
   probes_file='@path/to/probes.yml'
 ```
 
-Note that the `relabel_configs` of each scrape job doesn't need to be specified, and will be 
+Note that the `relabel_configs` of each scrape job doesn't need to be specified, and will be
 overridden by the charm with the needed labels and the correct Blackbox Exporter url.
 
+#### Dynamic Configuration
+
+The list of probes and the list of modules for probing can also be changed dynamically from other charms.
+The charm offers a relation to allow charms to dynamically export endpoints to be probed via Blackbox Exporter and custom modules for probing. Those are exported over the probes relation using the blackbox_exporter_probes interface:
+
+```shell
+requires:
+  probes:
+    interface: blackbox_exporter_probes
+```
+
+The probes provided dynamically by a charm are merged with the probes defined in a configuration file, same with the modules which are integrated in the blackbox-config file.
+In order for the charm defined probes to be probed via this charm all that is required is to relate the two charms with:
+
+```shell
+juju relate <charm> blackbox:probes
+```
+
+Charms that seek to provide probes for Blackbox Exporter, must do so using the provided blackbox_exporter_probes charm library. This library ensures that probes and modules defined by a charm are forwarded correctly to Prometheus, and the metrics displayed in the associated Grafana Dashboard.
+
 ## OCI Images
 This charm is published on Charmhub with blackbox exporter images from
 the official [quay.io/prometheus/blackbox-exporter].