Prep to move address_standardizer into extensions folder

git-svn-id: http://svn.osgeo.org/postgis/trunk@12860 b70326c6-7e19-0410-871a-916f4a2858ee
remove now part of extensions folder

git-svn-id: http://svn.osgeo.org/postgis/trunk@12861 b70326c6-7e19-0410-871a-916f4a2858ee
#2874 document move of address_standardizer to extensions folder.

git-svn-id: http://svn.osgeo.org/postgis/trunk@12862 b70326c6-7e19-0410-871a-916f4a2858ee