Add SVG converter, fix PDF rendering on ReadTheDocs

[Zeitsperre]

Pull Request Checklist:

• [ ] This PR addresses an already opened issue (for bug fixes / features)
  • This PR fixes #xyz
• [x] (If applicable) Documentation has been added / updated (for bug fixes / features).
• [ ] (If applicable) Tests have been added.
• [x] CHANGELOG.rst has been updated (with summary of main changes).
  • [x] Link to issue (:issue:number) and pull request (:pull:number) has been added.

What kind of change does this PR introduce?

• Adds an SVG converter to the PDF generating LaTeX dependencies

Does this PR introduce a breaking change?

It should not.

Other information:

What's going on here?

Some changes to the LaTeX engine on ReadTheDocs have been causing the SVG files referenced in the README.rst to be rendered as individual PDF files. I'm not certain why that is happening, but it was causing the latest and stable documentation builds to fail. This PR makes it so that instead of the README.rst being referenced directly by sphinx, instead it is copied and patched to not render the badges when building for PDF. This has fixed the issue.

[coveralls]

coverage: 81.343%. remained the same when pulling 0099fbadd75e1b022cf54b28a46189c86f5fe3f7 on fix-docs into db1239247d72d28dd1859648e46b1450db319bb7 on master.