[Add forge now] Add an accepted request to the scheduling process

In the request dashboard, the administrator could send the request to scheduling (this task needs further grooming to check technical use cases, for example obtaining a token to access the forge api)

Doc on how to save a forge : https://docs.softwareheritage.org/devel/swh-lister/save_forge.html#save-a-forge

To be explored : Must not be accessible to the moderator (admin only)

Add a task to scheduler in staging (automatic from UI)

MVP : manually phabricator task provide the administrator with the suggested command test on staging first

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Migrated from T4017 (view on Phabricator)