[multi-sources] call doexec rather than sqlexec since we do not want to call process_result (as there aren't any and this breaks with lgdb default)

[sources] hide some attributes from source edition form. Closes #2144160

[https] Allow configuration of anonymous access on https (closes #1971992) For now any anonymous access in denied on secured connection (https-url). This patch introduce a configuration option to control this behaviour. New instance will allow it. Old instance should stay as is during migration.