Add DWRL lab to OC wastewater export.

[klenwell]

There are a couple different labs used for OC wastewater data. They have lab IDs CAL3 and DWRL.

I initially used CAL3 because it seemed more complete. But it's been a couple weeks since its last update and recent data has seemed erratic and unreliable. So I updated the extract and export to include DWRL data as well. I've also update exports that depend on the wastewater data to be able to switch between the two more easily.

Trello card: https://trello.com/c/4lRjgzuU

Here's an example of the new output file format:

• oc-wastewater.csv

Here's what the export looks like when run from command line:

$ python app.py oc wastewater                                                    

OC COVID-19 Wastewater Data Export                                                                                      
=====================================                                                                                   

CSV Path: /home/klenwell/projects/covid-19/data/oc/oc-wastewater.csv                                                    
End Date: 2022-05-30                                                                                                    

Newest CAL3 Sample: 2022-05-17                                                                                          
Newest DWRL Sample: 2022-05-30                                                                                          

Lab Counts: {'CAL3': 366, 'DWRL': 128}                                                                                  

Start Date: 2021-06-28