v2021 ← v2022dev2 backports

• 93e71937 Move BOM file generation to commit for OSTree images
• 52094210 ostree: move boot files out from /boot
• 062c139b ostree: uefi: cleanup boot/efi empty directory
• 71150acb Drop duplicated listing of the locales package
• a915299f Move locales configuration at the beginning
• 29a477a5 Rename default-locale-c-utf8 to locale-default-c-utf8
• 88e587ec Fix locale generation by using locale.gen
• eb08fabd generate_bom: Fix the JSON syntax of the licensing report
• 35c2cedf generate_bom: Fix the typo in the --pretty flag
• 927f6c1a {sys,dev}root: Clean up apt lists and caches