Add support for archiving a submission

[int-y1]

fixes #1767

an admin needs judge.archive_submission to archive submissions. there are 2 ways to archive a submission:

1. go to /problem/<code>/manage/submission, turn on "Archive locked submissions", and click "Rejudge selected submissions"
   • my approach is to include locked submissions in the query, and then let Submissions.judge set is_archived to true
2. go to /admin/judge/submission/<code>/change/ and toggle "Is archived"

user-facing changes when a submission is archived:

• during point recalculation (e.g. /admin/judge/profile/ > Action > Recalculate scores): submission is not considered when recalculating points, problems solved, and pp
• /user/<name>/solved: submission no longer appears in "Points breakdown" and in the problems solved table
• /problem/<code>/rank/: submission no longer appears as a best solution
• /submissions/ and /problem/<code>/submissions/: submission becomes partly transparent and gets an archive icon. see screenshot.

there are no admin-facing changes when a submission is archived

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 47.50000% with 21 lines in your changes missing coverage. Please review.

Project coverage is 47.71%. Comparing base (fd7fb05) to head (3e796de).
Report is 69 commits behind head on master.

Files with missing lines	Patch %	Lines
judge/signals.py	37.50%	5 Missing ⚠️
judge/tasks/submission.py	33.33%	4 Missing ⚠️
judge/views/problem_manage.py	42.85%	4 Missing ⚠️
judge/models/submission.py	25.00%	3 Missing ⚠️
judge/admin/submission.py	33.33%	2 Missing ⚠️
judge/models/profile.py	0.00%	1 Missing ⚠️
judge/utils/problems.py	0.00%	1 Missing ⚠️
judge/views/user.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2411      +/-   ##
==========================================
+ Coverage   46.76%   47.71%   +0.95%     
==========================================
  Files         251      260       +9     
  Lines       13317    13747     +430     
==========================================
+ Hits         6228     6560     +332     
- Misses       7089     7187      +98     

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[Riolku]

Overall ty for working on this, it looks great :)

[Riolku]

Err, what does this part of the migration do?

[int-y1]

this is needed so that the permission archive_submission appears under /admin/auth/user/<id>/change/ > Available user permissions

[Ninjaclasher]

It would be nice if, in the places where we currently show locked instead of Rejudge, we give the option of Archive. Off the top of my head, this is currently in judge/admin/submission.py's judge_column, the submission row (templates/submission/row.html), and submission status/source (templates/submission/(status|source).html).

This would match the behaviour in other places (e.g. contest problem rejudge) where there is no check for is_locked and thus we go to Submission.judge and automatically archive.

Otherwise LGTM.

[int-y1]

• allow access to "Archive locked submissions". don't put this behind the "judge.archive_submission" permission.
• add is_archived=False to more queries