move poznan_pl to its own source

sepan_remodis_pl stopped supporting Poznan

doc/source/poznan_pl.md

@@ -0,0 +1,40 @@
+# Poznań
+
+Support for schedules provided by [Poznań](https://poznan.pl).
+
+## Configuration via configuration.yaml
+
+```yaml
+waste_collection_schedule:
+  sources:
+    - name: poznan_pl
+      args:
+        street_name: Święty Marcin
+        street_number: 1
+```
+
+### Configuration Variables
+
+**street_address**  
+*(string) (required)*
+
+**street_number**  
+*(string)(required)*
+
+All arguments must be provided.
+
+## Example
+
+```yaml
+waste_collection_schedule:
+  sources:
+    - name: poznan_pl
+      args:
+        street_name: Święty Marcin
+        street_number: 1
+```
+
+## How to get the source arguments
+
+You have to provide your street name and house number (eg 1 or 7/3).
+You can check if your address is covered by SepanRemondis provider at page [poznan.pl](https://www.poznan.pl/mim/odpady/harmonogramy.html)