pgsql: Create default roles

Create default roles

This creates an initial set of default roles which administrators may
use to grant access to, historically, superuser-only functions.  Using
these roles instead of granting superuser access reduces the number of
superuser roles required for a system.  Documention for each of the
default roles has been added to user-manag.sgml.

Bump catversion to 201604082, as we had a commit that bumped it to
201604081 and another that set it back to 201604071...

Reviews by José Luis Tallón and Robert Haas

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/7a542700df25eaf97b794bff63606176433dcdda

Modified Files
--------------
doc/src/sgml/func.sgml                  |  8 ++++--
doc/src/sgml/user-manag.sgml            | 51 +++++++++++++++++++++++++++++++++
src/backend/utils/adt/misc.c            |  8 ++++--
src/include/catalog/catversion.h        |  2 +-
src/include/catalog/pg_authid.h         |  8 +++++-
src/test/regress/expected/rolenames.out |  5 ++++
src/test/regress/sql/rolenames.sql      |  2 ++
7 files changed, 76 insertions(+), 8 deletions(-)