emulators/hyperv-is: Use kmod, support non-default prefix

USES= kmod correctly installs the kernel modules at /boot/modules
instead of /boot/kernel.  Also use the post-install target to support
prefixes other than /usr/local.

Suggested by:	bapt and bdrewery
graphics/py-pillow: fix build of tk extension

- Update to 2.6.0
- USES python

PR:		193958
Submitted by:	mva
Approved by:	koobs (maintainer)