New Catima logo and feature graphic

- Updated app icon assets (mipmaps & VectorDrawables)
- Updated feature graphic SVG (updated icon, changed fonts to match the new icon style)
- Updated feature graphic script (to account for the changed fonts)
- Created .design folder containing master design files
- Deleted old logo and fonts

Author: il-Luca

.design/README.txt

@@ -0,0 +1,4 @@
+VectorDrawable does not support all SVG features, such as shadows and masks.
+Therefore the ic_launcher files are slightly different from the master files: no shadows, minor color tweaks, path optimisation.
+Use ic_launcher_*.svg files to generate assets for the app icon
+Use master_*.svg files to generate other assets (e.g. feature graphic, playstore icon) or to rework the icon design