devel/py-python-gilt: Move to devel/gilt and update to 2.2.4
The upstream project changed languages from python to go. While there
is still a PYPI entry for this software
(https://pypi.org/project/python-gilt/), all it consists of is a
pip-package containing the compiled gilt binary and the usual pip
dist-info data. Since we're building a FreeBSD package here, we don't
need any of the pip metadata, and we can just install this as a
standard go module port.