EOL: Debian buster, Ubuntu mantic, i386 architecture

> On pgsql-pkg-debian I proposed this plan:
> 
> * Remove buster-pgdg from apt.pg.o (buster-lts was EOLed last month)
> 
> * Remove i386 from sid-pgdg (packages are still preserved on
>   apt-archive.postgresql.org)
> 
> * Upload postgresql-17 to Debian unstable, with all architectures
>   supported [*] (once rc1 is there)

The first three steps have happened now.

buster-pgdg has been copied to apt-archive.postgresql.org; the copy on
apt.postgresql.org will not receive any updates anymore and will be
removed in three weeks with the 17.0 release.

If you still need packages for buster, point your sources.list to
https://apt-archive.postgresql.org/pub/repos/apt/ buster-pgdg main

At the same time, mantic-pgdg has been copied over, and work on
supporting oracular-pgdg has begun.

TBD:

> * When re-uploading all extensions to Debian to transition them from
>   16 to 17, disable extensions on 32-bit archs. Adding this should do
>   the trick:
> 
>   Build-Depends: architecture-is-64-bit <!pkg.postgresql.32-bit>,
> 
>   That way, people could still build extension packages manually if
>   they really wanted (dpkg-buildpackage -Ppkg.postgresql.32-bit).
> 
> * Remove postgresql-16 from unstable

Christoph