moving from contrib to bin

Let's take another crack at moving stuff out of contrib. Nobody likes
contrib. The task is only finding something that most people like better.

Last time this was attempted, the discussion got lost in exactly which
extensions are worthy enough to be considered official or something like
that. I want to dodge that here by starting at the opposite end:

1. move programs to src/bin/

2. move test things to src/test/ (I had that in my notes, but someone
already did that, so the stars must be aligned.)

3. deal with extensions later

Here are the contrib programs:

oid2name
pg_archivecleanup
pg_standby
pg_test_fsync
pg_test_timing
pg_upgrade
pg_xlogdump
pgbench
vacuumlo

The proposal would basically be to mv contrib/$x src/bin/$x and also
move the reference pages in the documentation.

We could consider alternative arrangements, if there is interest, such
as moving vacuumlo to scripts or moving pg_archivecleanup and pg_standby
into one directory. It doesn't matter very much to me.

There is precedent for this: Some time ago we moved reindexdb from
contrib to scripts.

Besides moving things out of contrib, there is also a practical
motivation for this. Putting both client and server programs into
contrib creates issues for packagers. One would have to create a
separate -contrib-client package to package this properly. Not to
mention packaging a bunch of unrelated extensions with these programs.
If we make these normal programs in src/bin/, packagers can put them
into the normal -client and -server packages, and everything will fall
into place.

Besides, a number of packagers have been treating pg_upgrade specially
and moved it out of contrib, so this would just be catching up with
reality a bit.

Comments?