Package fossology-nomossa for buster-swh suite

New staging worker got created from scratch to try and run the same indexers as the production does. It's failing to install for the fossology indexer since that dependency is only available for jessie/stretch.

This needs to be rebuilt for buster (and uploaded in our debian repository).

root@pergamon:/srv/softwareheritage/repository# reprepro ls fossology-nomossa
fossology-nomossa | 3.1-1~bpo8~swh+1 |      jessie | amd64
fossology-nomossa | 3.1-1~bpo9~swh+1 | stretch-swh | amd64

root@pergamon:/srv/softwareheritage/repository# debdiff pool/main/f/fossology/fossology-nomossa_3.1-1~bpo*
[The following lists of changes regard files as different if they have
different names, permissions or owners.]

Files in second .deb but not in first
-------------------------------------
-rw-r--r--  root/root   /usr/share/doc/fossology-nomossa/changelog.gz

Control files: lines which differ (wdiff format)
------------------------------------------------
Installed-Size: [-548-] {+644+}
Version: [-3.1-1~bpo8~swh+1-] {+3.1-1~bpo9~swh+1+}

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Migrated from T3039 (view on Phabricator)