[Merge] ~seb128/ubuntu-seeds/+git/ubuntu:simplify-language-lists into ~ubuntu-core-dev/ubuntu-seeds/+git/ubuntu:mantic

[Jeremy Bícha]

Could you add these packages to the supported file for now since we aren't sure we want to demote LibreOffice to universe yet?
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https://code.launchpad.net/~seb128/ubuntu-seeds/+git/ubuntu/+merge/446401
Your team Ubuntu Core Development Team is requested to review the proposed merge of ~seb128/ubuntu-seeds/+git/ubuntu:simplify-language-lists into ~ubuntu-core-dev/ubuntu-seeds/+git/ubuntu:mantic.