pgsql: Remove RADIUS support.

Remove RADIUS support.

Our RADIUS implementation supported only the deprecated RADIUS/UDP
variant, without the recommended Message-Authenticator attribute to
mitigate against the Blast-RADIUS vulnerability. By now, popular RADIUS
servers are expected to generate loud warnings or reject our
authentication attempts outright.

Since there have been no user reports about this, it seems unlikely that
there are users.

Reviewed-by: Álvaro Herrera <alvherre(at)kurilemu(dot)de>
Reviewed-by: Aleksander Alekseev <aleksander(at)tigerdata(dot)com>
Reviewed-by: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Reviewed-by: Jacob Champion <jacob(dot)champion(at)enterprisedb(dot)com>
Reviewed-by: Michael Banck <mbanck(at)gmx(dot)net>
Discussion: https://postgr.es/m/CA%2BhUKG%2BSH309V8KECU5%3DxuLP9Dks0v9f9UVS2W74fPAE5O21dg%40mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/a1643d40b308911cc725e62d3c5f7904b426aa09

Modified Files
--------------
doc/src/sgml/appendix-obsolete-auth-radius.sgml | 20 +
doc/src/sgml/appendix-obsolete.sgml | 1 +
doc/src/sgml/client-auth.sgml | 128 ------
doc/src/sgml/filelist.sgml | 1 +
src/backend/libpq/auth.c | 511 +-----------------------
src/backend/libpq/hba.c | 216 ----------
src/backend/libpq/pg_hba.conf.sample | 4 +-
src/backend/utils/adt/hbafuncs.c | 19 -
src/include/libpq/hba.h | 9 -
src/tools/pgindent/typedefs.list | 2 -
10 files changed, 25 insertions(+), 886 deletions(-)