release: unbreak podman merged image generation

[dch]

Summary

Ensure there is no overlap of names used to generate OCI images.

The release tooling uses globs to filter and select files for merging
into the architecture-independent images. The previous naming used
"toolchain", which is a strict subset of "notoolchain", and broke the
expected glob result, by returning multiple names.

[dch]

LGTM here. I failed to get thermite to run at all, but the only change should be to amend:

45:oci_images="static dynamic runtime no-toolchain with-toolchain"

A local podmanic loop ran fine:

for r in 15.0-ALPHA3
  for t in static dynamic runtime with-toolchain no-toolchain
    doas podmanic \
      /usr/obj/usr/src/arm64.aarch64/release/container-image-$t.txz \
      /usr/obj/usr/src/amd64.amd64/release/container-image-$t.txz \
      cr.skunkwerks.at/freebsd-$t:(string lower $r) cr.skunkwerks.at/freebsd-$t:15.snap
  end
end

# podman image search --list-tags cr.skunkwerks.at/freebsd-with-toolchain
NAME                                     TAG
cr.skunkwerks.at/freebsd-with-toolchain  15.snap
cr.skunkwerks.at/freebsd-with-toolchain  15.0-alpha3
# podman image search --list-tags cr.skunkwerks.at/freebsd-no-toolchain
NAME                                   TAG
cr.skunkwerks.at/freebsd-no-toolchain  15.0-alpha3
cr.skunkwerks.at/freebsd-no-toolchain  15.snap