Move module i18n strings out of core & into module

[benkeen]

Looks like this is an old legacy code from pre FT 2. These i18n strings should be moved from the Core to the module:

• notify_file_deleted
• notify_file_not_deleted_no_exist,
• notify_file_not_deleted_permissions
• notify_file_not_deleted_unknown_error
• notify_file_too_large
• notify_submission_no_field_id
• notify_submission_updated_file_problems
• notify_unsupported_file_extension

[benkeen]

This isn't fully possible yet due to this limitation: https://github.com/formtools/core/issues/437

But I'll remove everything except the lang strings used in the Edit/View smarty content.