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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REL_10_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/0ce8e49b224300fe895f5cda6b8e45d80bbdf860

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(-)