Generate SVG images for the preview-latex package.

Installation:
This package requires the preview-latex package
(see https://www.gnu.org/software/auctex/manual/preview-latex.html).
It is tested with version 13.0.12 of the preview-latex package.
Furthermore, you need a working LaTeX installation and
the programm `dvisvgm' installed on your computer (see https://dvisvgm.de/).

Put preview-dvisvgm.el somewhere in your `load-path' and require it
your init file (e.g., "~/.emacs.d/init.el") with

(require 'preview-dvisvgm)

Note, that this package adds an entry for dvisvgm to preview-image-creators.
(Currently, this appears to be a customization which it isn't.  This is a known dept.)

Usage:
If you like preview-latex to generate svg images customize option
`preview-image-type' to "dvisvgm".