New: prepare for extend GED module

htdocs/ecm/class/ecmdirectory.class.php

htdocs/ecm/docdir.php

htdocs/install/mysql/migration/3.2.0-3.3.0.sql

htdocs/install/mysql/tables/llx_ecm_directories.key.sql

htdocs/install/mysql/tables/llx_ecm_directories.sql

htdocs/install/mysql/tables/llx_ecm_documents.key.sql

htdocs/install/mysql/tables/llx_ecm_documents.sql

htdocs/install/mysql/tables/llx_element_tag.key.sql

htdocs/install/mysql/tables/llx_element_tag.sql

htdocs/install/upgrade.php