Bring aptftp.conf across from the download server

It lived unversioned in pgaupload's home directory on paxsor, which also
made it writable by the account the publishing scripts run as, despite
being an input to what gets indexed and therefore to what gets signed.

Taking it here settles both: changing the repository's Origin, Label or
architectures becomes a reviewed commit, and the copy on the server can
become root owned.

The default architecture list drops i386 to match. apt-ftparchive has
been writing dists/pgadmin4/main/binary-i386/Packages for years, but
Architectures in the Release file has only ever said 'amd64 all', so no
client has been able to reach that index through the signed metadata.
Nothing that works today stops working.

pkg/publish/aptftp.conf

@@ -0,0 +1,22 @@
+// Configuration for apt-ftparchive, brought across from
+// /home/pgaupload/aptftp.conf on the download server so that it is version
+// controlled alongside the scripts that use it.
+//
+// Architectures is overridden on the apt-ftparchive command line by
+// rebuild-apt-repo.sh, from the same list it indexes, so that the set of
+// architectures indexed and the set advertised in the signed Release file
+// cannot disagree. The value here is the default that override supplies.
+
+APT::FTPArchive::Release {
+  Origin "pgAdmin Development Team";
+  Label "pgAdmin 4";
+  Suite "pgadmin4";
+  Architectures "amd64 all";
+  Components "main";
+  Description "pgAdmin 4 - Development Tools for PostgreSQL";
+};
+Default {
+        Packages::Compress ". gzip bzip2";
+        Sources::Compress ". gzip bzip2";
+        Contents::Compress ". gzip bzip2";
+};

pkg/publish/rebuild-apt-repo.sh

@@ -16,7 +16,7 @@
 set -e
 
 ROOT=/var/ftp/pgadmin4
-ARCHES="all amd64 i386"
+ARCHES="amd64 all"
 DEFAULT_ROOT=${ROOT}
 DEFAULT_ARCHES=${ARCHES}