pgsql: Move snowball_create.sql creation into perl file

Move snowball_create.sql creation into perl file

This is in preparation for building postgres with meson / ninja.

We already have duplicated code for this between the make and msvc
builds. Adding a third copy seems like a bad plan, thus move the generation
into a perl script.

As we don't want to rely on perl being available for builds from tarballs,
generate the file during distprep.

Author: Peter Eisentraut <peter(at)eisentraut(dot)org>
Author: Andres Freund <andres(at)anarazel(dot)de>
Discussion: https://postgr.es/m/5e216522-ba3c-f0e6-7f97-5276d0270029@enterprisedb.com

Branch
------
master

Details
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https://git.postgresql.org/pg/commitdiff/b3a0d8324cf1f02c04a7099a436cfd68cfbf4566

Modified Files
--------------
src/backend/snowball/Makefile | 106 ++++++-----------------
src/backend/snowball/snowball_create.pl | 148 ++++++++++++++++++++++++++++++++
src/tools/msvc/Install.pm | 36 +-------
3 files changed, 179 insertions(+), 111 deletions(-)