N°6964 - Add API to allow modules to register files to include in the backup (#547)

* Allow to include backup extra file via interface

* Update application/applicationextension.inc.php

Co-authored-by: Thomas Casteleyn <thomas.casteleyn@me.com>

* Add iBackupExtraFilesExtension to plugin list

* decouple extra_files via config and interface

* Add unit tests for iBackupExtraFilesExtension

* Enable recursive creation of destination directories

* Update application/applicationextension.inc.php

Co-authored-by: Molkobain <lajarige.guillaume@free.fr>

* Update setup/backup.class.inc.php

Co-authored-by: Molkobain <lajarige.guillaume@free.fr>

* Update tests/php-unit-tests/unitary-tests/application/applicationextension/ApplicationExtensionTest.php

Co-authored-by: Molkobain <lajarige.guillaume@free.fr>

* Update application/applicationextension.inc.php

Co-authored-by: Molkobain <lajarige.guillaume@free.fr>

* Update core/metamodel.class.php

Co-authored-by: Molkobain <lajarige.guillaume@free.fr>

* Update setup/backup.class.inc.php

Co-authored-by: Molkobain <lajarige.guillaume@free.fr>

---------

Co-authored-by: Thomas Casteleyn <thomas.casteleyn@me.com>
Co-authored-by: Molkobain <lajarige.guillaume@free.fr>

application/applicationextension.inc.php

@@ -2281,4 +2281,22 @@ interface iKPILoggerExtension
      * @return mixed
      */
     public function LogOperation($oKpiLogData);
-}
+}
+
+/**
+ * Implement this interface to add files to the backup
+ *
+ * @api
+ * @since 3.2.0
+ */
+interface iBackupExtraFilesExtension
+{
+	/**
+	 * Returns an array of files and directories to be included in the backup
+	 *
+	 * @api
+	 *
+	 * @return string[]
+	 */
+	public function GetExtraFiles(): array;
+}