Add support for retrying tasks in admin

[gmuj]

Hi, I have been using this code to retry tasks from admin within the old django-celery library. Maybe other people will find this useful.

[codecov[bot]]

Codecov Report

:exclamation: No coverage uploaded for pull request base (master@5230e4c). Click here to learn what that means. The diff coverage is 44.44%.

@@          Coverage Diff           @@
##             master    #2   +/-   ##
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  Coverage          ?   73%           
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  Files             ?    10           
  Lines             ?   426           
  Branches          ?    54           
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  Hits              ?   311           
  Misses            ?   111           
  Partials          ?     4

Impacted Files	Coverage Δ
django_celery_monitor/admin.py	53.07% <44.44%> (ø)

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[sameerkumar18]

In case someone is looking for a Django Admin Action to manually retry Celery tasks, check this