Convert catalog logo text to path

The "ICF Study Catalog" text in the catalog logo is converted to path
to make the display independent from the fonts installed on the user's
computer. Fixes #51 (missing font caused the text to be cut off).

The font used is Hanken Grotesk (OFL-1.1 license); it should work
nicely alongside the FZJ logo (FZJ's official font is Weissenhof
Grotesk, but it is proprietary).

Font (GitHub): https://github.com/marcologous/hanken-grotesk/
Font (Google): https://fonts.google.com/specimen/Hanken+Grotesk

Suggested-by: Christian Mönch <[email protected]>