Add footpath to topics

Author: SylviaMaria123

ohsome_quality_api/projects/projects.yaml

@@ -50,3 +50,8 @@ bkg:
   name: TODO
   description: >-
     something that is still a TODO
+
+silverways:
+  name: Silver Ways
+  description: >-
+    https://heigit.org/silver-ways/

ohsome_quality_api/topics/presets.yaml

@@ -164,6 +164,31 @@ cycleway:
     - core
     - bkg
 
+footpath:
+  name: Footpath
+  description: >-
+    All linear OSM features commonly used for walking, including dedicated pedestrian paths,
+    shared-use paths, and roads where foot traffic is allowed or sidewalks exist.
+  endpoint: elements
+  aggregation_type: length
+  filter: >-
+    (
+      (highway=footway)
+      or (highway=path and (foot=designated or foot=yes))
+      or (highway=pedestrian)
+      or (highway=steps)
+      or (highway=cycleway and foot=yes)
+      or (sidewalk=* and highway!=motorway)
+      or (foot=yes)
+    )
+    and geometry:line
+  source: https://wiki.openstreetmap.org/wiki/Key:foot
+  indicators:
+    - mapping-saturation
+    - currentness
+  projects:
+    - silverways
+
 poi:
   name: POI
   description: Points of interest