Split $helptxt['attachment_manager_settings'] into individual strings

Signed-off-by: Suki <suki@missallsunday.com>
Brand new language strings

Signed-off-by: Suki <suki@missallsunday.com>
Corrections

Signed-off-by: Suki <suki@missallsunday.com>
Merge pull request #639 from MissAllSunday/attachment_help_strings

Attachment help strings