Authenticated users should be able to browse their save code now requests

Currently, only the whole set of save code now requests can be browsed through the Web UI.

That's not really handful for a user who wants to know the statuses of the requests he submitted.

We should give the possibility for an authenticated user to browse the save requests he created in a new tab of the user profile page.

This would require to extend the save code now request django model with a new field storing the id of the user that submits it.

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Migrated from T3272 (view on Phabricator)