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
------
REL_11_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/721963f24ae8c2097bb7c44cc0f428740f6cf2a7

Modified Files
--------------
doc/src/sgml/install-windows.sgml | 19 +++++++-------
src/tools/msvc/MSBuildProject.pm | 25 ++++++++++++++++++
src/tools/msvc/README | 13 +++++-----
src/tools/msvc/Solution.pm | 28 ++++++++++++++++++++
src/tools/msvc/VSObjectFactory.pm | 54 +++++++++++++++++++++++++++++----------
5 files changed, 111 insertions(+), 28 deletions(-)