Shifted TZ discussion out of best practices into prerequisites.sgml

Shifted superuser discussion into security.sgml, and reformatted somewhat.

Some other tagging fixes as consequence
(cherry picked from commit de659198e769aa34c5ca126e168b0342af46701e)

Conflicts:

	doc/adminguide/bestpractices.sgml
	doc/adminguide/security.sgml
	doc/adminguide/slony.sgml

Branch
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REL_2_0_STABLE

Details
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http://git.postgresql.org/gitweb?p=slony1-engine.git;a=commitdiff;h=72a148885f3fa50ab9d48e873323c786143fbce0

Modified Files
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doc/adminguide/bestpractices.sgml |   43 ----------------
doc/adminguide/failover.sgml      |   23 +++++++++
doc/adminguide/prerequisites.sgml |   38 +++++++++++++-
doc/adminguide/security.sgml      |   99 ++++++++++++++++++++++++------------
doc/adminguide/slonik_ref.sgml    |    2 -
doc/adminguide/slony.sgml         |    1 -
6 files changed, 125 insertions(+), 81 deletions(-)