pgsql: Split out documentation of SSL parameters into their own section

Split out documentation of SSL parameters into their own section

Split the "Authentication and Security" section into two separate
sections "Authentication" and "SSL". The latter part has gotten much
longer over time, and doesn't primarily have to do with authentication.

Also, the row_security parameter was inconsistently categorized, so
clean that up while we're here.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/7404e77cc1192855afef28ae557993ba6f35c16e

Modified Files
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doc/src/sgml/config.sgml | 233 +++++++++++++-------------
src/backend/utils/misc/guc.c | 38 +++--
src/backend/utils/misc/postgresql.conf.sample | 41 ++---
src/include/utils/guc_tables.h | 3 +-
4 files changed, 165 insertions(+), 150 deletions(-)