pgsql: Add ssl_library preset parameter

Add ssl_library preset parameter

This allows querying the SSL implementation used on the server side.
It's analogous to using PQsslAttribute(conn, "library") in libpq.

Reviewed-by: Daniel Gustafsson <daniel@yesql.se>

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/98efa76fe313f62f84b94cd1f46c913c221b41fe

Modified Files
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doc/src/sgml/config.sgml | 16 ++++++++++++++++
src/backend/libpq/be-secure.c | 1 +
src/backend/utils/misc/guc.c | 15 +++++++++++++++
src/include/libpq/libpq.h | 1 +
src/test/ssl/t/001_ssltests.pl | 7 ++++++-
5 files changed, 39 insertions(+), 1 deletion(-)