Moving Wolfi to usr-merge and sbin-merge

[xnox]

Majority of glibc based distributions use usr-merged file system layout. Some are also moving sbin merged systems. For wolfi to remain a drop-in replacement for these, it is best for Wolfi to adopt these too.

References:

• https://systemd.io/THE_CASE_FOR_THE_USR_MERGE/
• https://fedoraproject.org/wiki/Changes/Unify_bin_and_sbin
• https://discussion.fedoraproject.org/t/f40-change-proposal-unify-usr-bin-and-usr-sbin-system-wide/99853/29

Alpine is working on such a move, but it currently will likely co-incide with upgrade to apk-tools v3:

• https://gitlab.alpinelinux.org/alpine/apk-tools/-/merge_requests/203
• https://gitlab.alpinelinux.org/alpine/tsc/-/issues/89

It generally should be safe to perform usr-merge in stages:

• Move /sbin binaires to /usr/bin and complete /sbin usr-merge - DONE March 3rd 2025
• Move /bin binaries to /usr/bin and complete /bin usr-merge - DONE March 6th 2025
• Move /usr/sbin binaries to /usr/bin and complete /usr/sbin merge - DONE March 31st 2025
• Move /lib to usr/lib and complete /lib usr-merge - DONE June 23rd 2025

These are ordered from lowest/largest impact and risk. And possibly we don't do the last one per-se, or do it with smallest number of moves remaining.

[xnox]

/sbin has been merged into /usr/bin, image build are in progress.

[xnox]

/bin has been merged into /usr/bin

[a-crate]

/usr/sbin was merged into /usr/bin on March 31st.

[a-crate]

/lib was merged into /usr/lib on June 23rd.

This merge required a number of changes in build tooling due to the way they build the base filesystem and how it can conflict with wolfi-baselayout. When building new versions of wolfi, you should use newer versions of melange, apko, and rules_apko for bazel.

Specifically, versions at or greater than:

apko v0.27.6
melange v0.23.15
rules_apko for bazel v1.5.3

[a-crate]

All usr-merge targets above are now complete.