converters/py-svglib: Re-add port
The port is being maintained by upstream fairly regularly again after a
lengthy hiatus:
Svglib is a pure-Python library for reading SVG files and converting
them (to a reasonable degree) to other formats using the ReportLab Open
Source toolkit.
Used as a package you can read existing SVG files and convert them into
ReportLab Drawing objects that can be used in a variety of contexts,
e.g. as ReportLab Platypus Flowable objects or in RML.
As a command-line tool it converts SVG files into PDF ones (but adding
other output formats like bitmap or EPS is really easy and will be
better supported, soon).