adding St. Pölten (#2027)

* adding St. Pölten

* fix country + ./update_docu_links.py

---------

Co-authored-by: 5ila5 <5ila5@users.noreply.github.com>

doc/ics/st-poelten_at.md

@@ -0,0 +1,27 @@
+# Abfallwirtschaft der Stadt St. Pölten
+
+Abfallwirtschaft der Stadt St. Pölten is supported by the generic [ICS](/doc/source/ics.md) source. For all available configuration options, please refer to the source description.
+
+
+## How to get the configuration arguments
+
+- Goto <https://www.st-poelten.at/sonstiges/17653-abfallkalender> and click "Inhalte von services.st-poelten.at laden"
+- fill out your address
+- klick F12 or start the dev-mode on your browser another way
+- klick on "Download Kalenderexport" and discard or save the file (you'll not need it for that)
+- find the link for the ics-file in the "Network"-section of your browsers Dev-tools
+- copy the link - for the Landhaus it's https://services.infeo.at/awm/api/st.p%C3%B6lten/wastecalendar/v2/export/?calendarId=135&cityId=162&streetId=124691&housenumber=1&outputType=ical
+- (the only values changing here shall be "streetId" and "housenumber")   
+
+## Examples
+
+### Oppach
+
+```yaml
+waste_collection_schedule:
+  sources:
+    - name: ics
+      args:
+        split_at: ' & '
+        url: https://services.infeo.at/awm/api/st.p%C3%B6lten/wastecalendar/v2/export/?calendarId=135&cityId=162&streetId=124691&housenumber=1&outputType=ical
+```