For a long time, Moodle has had the feature to force the language
for a whole course. This change adds the same feature at activity
level.
The course-level feature was controlled by a capability
moodle/course:setforcedlanguage, and I decided to use the same
capability to control this feature. I think a new capability would be
overkill.
This allows the teacher to define what students are supposed to submit
(online text and/or attachment) and if the given submission part is
required or optional.
