MDL-38603 Deprecate usepeerassessment setting in Workshop
There was a plan to make use of it initially when Workshop was rewritten
for Moodle 2.0. The idea was that the Workshop could be switched into a
simplified mode where teachers only make assessments (with all the
grading strategies available). But things evolved since then and now we
have Advanced grading methods available in the new Assignment module
that solves the use case well. So, having this option available is not
only confusing but - looking at the code - pretty useless.
For now, I am just hiding the setting from the settings form and the
code always considers it as if it was enabled. In the future, the field
can disappear from the database, too.
