Switch the default font from Montserrat to Roboto (fix #75)

This ensures that the font is the same as the default font on
Android devices, leading to more visual consistency.

Author: ENT8R

fonts/Montserrat-Bold.woff

@@ -1,6 +1,6 @@
 global:
     language: false # intended to be overwritten by StreetComplete
-    text_font_family: 'Montserrat'
+    text_font_family: 'Roboto'
     text_stroke_color: 'white'
     text_stroke: { color: global.text_stroke_color, width: 2.5px }
     text_places_stroke: { color: global.text_stroke_color, width: 2.5px }
@@ -83,15 +83,6 @@ sources:
         url: https://tiles.map-data.de/vector/v1/512/all/{z}/{x}/{y}.mvt
         max_zoom: 16
 
-fonts:
-    Montserrat:
-        - weight: 400
-          url: fonts/Montserrat-Regular.woff
-        - weight: 500
-          url: fonts/Montserrat-Medium.woff
-        - weight: 700
-          url: fonts/Montserrat-Bold.woff
-
 textures:
     oneway-arrow:
         url: images/[email protected]