split math/py-numpy

I'd like to go ahead and split numpy into python2 and python3 ports so we
can unblock updating numpy.

Attached is the py2-numpy port with the main diff being shown below. After
this goes in I can update the py3 port and the various consumers.

ok?

diff -x CVS -Nur py-numpy/Makefile py2-numpy/Makefile
--- py-numpy/Makefile Sun Jun 13 13:13:33 2021
+++ py2-numpy/Makefile Sun Jun 13 13:04:40 2021
@@ -1,6 +1,6 @@
# $OpenBSD: Makefile,v 1.61 2021/05/21 19:50:32 kmos Exp $

-COMMENT= fast array and numeric programming library for Python
+COMMENT= fast array and numeric programming library for Python 2

MODPY_EGG_VERSION= 1.16.6
DISTNAME= numpy-${MODPY_EGG_VERSION}
@@ -20,9 +20,7 @@
MODULES= lang/python \
fortran

-FLAVORS= python3
-FLAVOR = python3
-
+MODPY_VERSION = ${MODPY_DEFAULT_VERSION_2}
MODPY_PI = Yes
MODPY_SETUPTOOLS= Yes
MODPY_DISTUTILS_BUILDARGS = --fcompiler=gnu95
diff -x CVS -Nur py-numpy/pkg/PLIST py2-numpy/pkg/PLIST
--- py-numpy/pkg/PLIST Mon Jan 4 09:06:34 2021
+++ py2-numpy/pkg/PLIST Sun Jun 13 13:11:59 2021
@@ -1,103 +1,87 @@
+@pkgpath math/py-numpy