profiles/*/pkglist{,-build}: aggressively strip non-end-user packages.

No integrity guarantees kept. New package selection needs to be installation-
tested.
profiles, configs: merge cpu-arch-* into main; rip out the former.

Package lists for i686 and x86_64 have finally converged. Architecture-specific
packages (the toolchain) are currently installed by other means.
profiles/main: pkglist: sweep clean, pass 2.