Added documentation for commands to manage users and view actors

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

docs/administration/CLI tasks/manage_actors.md

@@ -0,0 +1,17 @@
+# Manage actors
+
+!!! tip "Environment"
+    You need to run these commands with the appropriate environment loaded
+
+## List all available commands 
+```bash
+mix mobilizon.actors
+```
+
+## Show an actors details
+
+```bash
+mix mobilizon.actors.show
+```
+
+In addition to basic informations, it also tells which user the profile belongs to, if local.