Author: Paul Holden
MDL-78946 tool_mfa: define factor subplugin type language strings.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=21ba055889c5362c7785dea569be00756264d531
http://github.com/moodle/moodle/commit/21ba055889c5362c7785dea569be00756264d531
+ 4.3 en [subplugintype_factor,tool_mfa]
+ 4.3 en [subplugintype_factor_plural,tool_mfa]