Merge branch 'mj/broken' into 'devel'

bin/fix-submits

db/db.ddl

db/upgrade-20210315.sql

mo/db.py

mo/jobs/submit.py

mo/submit.py

mo/web/org_contest.py

mo/web/templates/org_contest_solutions.html

mo/web/templates/org_submit_list.html

mo/web/templates/parts/org_solution_table.html

mo/web/templates/user_contest.html

mo/web/templates/user_contest_task.html

mo/web/user.py

mo/web/util.py