Add support for Birmingham City Council (UK), birmingham.gov.uk (#2049)

* Add support for Birmingham City Council (UK), birmingham.gov.uk

* Update code logic of `birmingham_gov_uk` to reduce indentation

* Update `birmingham_gov_uk` test cases to demonstrate integer UPRN's

* Be more resilient to unknown collection types, and still return them, just with an "question mark" icon

* reformatting

---------

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

doc/source/birmingham_gov_uk.md

@@ -0,0 +1,51 @@
+# Birmingham City Council
+
+Support for schedules provided by [Birmingham City Council](https://www.birmingham.gov.uk/), in the UK.
+
+## Configuration via configuration.yaml
+
+```yaml
+waste_collection_schedule:
+    sources:
+    - name: birmingham_gov_uk
+      args:
+        uprn: UNIQUE_PROPERTY_REFERENCE_NUMBER
+        postcode: POSTCODE
+```
+
+### Configuration Variables
+
+**uprn**<br>
+*(string)*
+
+The "Unique Property Reference Number" for your address. You can find it by searching for your address at https://www.findmyaddress.co.uk/.
+
+**postcode**<br>
+*(string)*
+
+The Post Code for your address. This needs to match the postcode corresponding to your UPRN.
+
+## Example
+```yaml
+waste_collection_schedule:
+    sources:
+    - name: birmingham_gov_uk
+      args:
+        uprn: 100070321799
+        postcode: B27 6TF
+```
+
+## Returned Collections
+This source will return the next collection date for each container type.
+
+## Returned collection types
+
+### Household Collection
+Grey lid rubbish bin is for general waste.
+
+### Recycling Collection
+Green lid recycling bin is for dry recycling (metals, glass and plastics).
+Blue lid recycling bin is for paper and card.
+
+### Green Recycling Chargeable Collections
+Green Recycling (Chargeable Collections).