MDL-70795 reportbuilder: custom report filters editor.

Implement module for filters editing, allowing the report
editor to define which filters are available when users
are viewing the report.

These filters allow those users viewing the report to further
limit the data being displayed (after conditions have been
applied), by selecting their own values for each filter.

Co-authored-by: Paul Holden <[email protected]>

user/classes/reportbuilder/datasource/users.php

@@ -61,6 +61,7 @@ class users extends datasource {
 
         $userentityname = $userentity->get_entity_name();
         $this->add_columns_from_entity($userentityname);
+        $this->add_filters_from_entity($userentityname);
         $this->add_conditions_from_entity($userentityname);
     }
 
@@ -73,6 +74,15 @@ class users extends datasource {
         return ['user:fullname', 'user:username', 'user:email'];
     }
 
+    /**
+     * Return the filters that will be added to the report once is created
+     *
+     * @return string[]
+     */
+    public function get_default_filters(): array {
+        return ['user:fullname', 'user:username', 'user:email'];
+    }
+
     /**
      * Return the conditions that will be added to the report once is created
      *