docker: type-agnostic lifecycle, profiling for all distros, legacy crossbuild aliases

docker: type-agnostic lifecycle, profiling for all distros, legacy crossbuild aliases

Splits the surface area further: docker.mk owns the generic image /
container / test machinery for every TYPE; crossbuild.mk is now a
thin alias layer (crossbuild.* -> docker.crossbuild.*) plus the
legacy crossbuild.help. DOCKER_TEST is the renamed type-parameterised
form of the old crossbuild test cycle, so docker.<type>.<image>.test
exists for every (image, type).

Profiling is no longer ubuntu24-only. A new profiling.rpm.m4 mirrors
the deb variant (valgrind, gperftools, heaptrack, kcachegrind, libkqueue
rebuild with debug symbols, FlameGraph, Inferno) using Rocky package
names, and common.rpm.debuginfo.m4 / common.deb.dbgsym.m4 are now
included unconditionally from both ci.* and crossbuild.* templates.
The deb repo URL was wrong (debian-debug.debian.net is unresolvable);
swapped to debug.mirrors.debian.org. The rpm side now goes through
`dnf debuginfo-install` (via dnf-plugins-core) so Rocky's per-version
debug-repo naming shifts don't break the build.