pgsql: Add support for Visual Studio 2019 in build scripts

Add support for Visual Studio 2019 in build scripts

This adjusts the documentation and the scripts related to the versions
of Windows SDK supported.

Author: Haribabu Kommi
Reviewed-by: Andrew Dunstan, Juan José Santamaría Flecha, Michael
Paquier
Discussion: /messages/by-id/CAJrrPGcfqXhfPyMrny9apoDU7M1t59dzVAvoJ9AeAh5BJi+UzA@mail.gmail.com
Backpatch-through: 9.4

Branch
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REL9_4_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/d49c127d90f94579a13106d4e7b198d04e5eea88

Modified Files
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doc/src/sgml/install-windows.sgml | 21 ++++++++-------
src/tools/msvc/MSBuildProject.pm | 25 ++++++++++++++++++
src/tools/msvc/README | 13 ++++-----
src/tools/msvc/Solution.pm | 28 ++++++++++++++++++++
src/tools/msvc/VSObjectFactory.pm | 55 +++++++++++++++++++++++++++++++--------
5 files changed, 115 insertions(+), 27 deletions(-)